birth defects in victoria 1999—2000/media/health/files...5.25 trisomy 21 109 5.26 trisomy 13 112...

Birth Defects in Victoria 1999—2000

Perinatal Data Collection Unit Public Health Department of Human Services Victoria 2002

Merilyn Riley Jane Halliday 2002 Perinatal Data Collection Unit GPO Box 4003 Melbourne 3001 Tel (03) 9616 2696 Fax (03) 9616 2700

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Birth Defects in Victoria 1999—2000, Perinatal Data Collection Unit, Public Health, Victorian Government Department of Human Services, September 2002, Melbourne, Victoria. ISBN: 0 7311 6161 0 ©State of Victoria 2002. This publication is copyright. No part may be reproduced by any process except in accordance with the provisions of the Copyright Act 1968. For further information and copies of this report please contact: Perinatal Data Collection Unit, GPO Box 4003, Melbourne 3001. Tel (03) 9616 2696 Fax (03) 9616 2700 This report is also available on the Internet: http://www.dhs.vic.gov.au/phd/perinatal/index.htm Suggested citation of this report: Riley M & Halliday J, Birth Defects in Victoria 19992000, Perinatal Data Collection Unit, Victorian Government Department of Human Services, Melbourne, 2002

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Contents

Acknowledgments 5 Abbreviations 6 Definitions 7 Highlights 9 1. Introduction 1.1 Background 11 1.2 Purposes of the BDR 11 1.3 Inclusion Criteria 11 1.4 Sources of Notification 12 1.5 Data Items 12 1.6 Data Quality 12 1.7 Confidentiality 13 1.8 Explanatory Notes 13 1.9 Terminations of Pregnancy 14 1.10 Statistics 14 1.11 Regional Variations 15 1.12 Previous Reports 15 2. Summary Tables 2.1 Birth Defects by Year, 19832000 17 2.2 Comparison of Prevalence of Birth Defects, 19831994, 19951998 and 19992000 18 2.3 Order of Prevalence of Twenty Seven Selected Defects, 19992000 19 2.4 Summary of Patterns for Twenty Four Selected Defects, 19992000 20 2.5 Birth Defects by Four-Digit Code, 19992000 2.6 Indications for Terminations of Pregnancy for a Birth Defect 27 Before 20 weeks Gestation, 19892000 3. Birth Defect Cases by Selected Infant Factors 3.1 Birth Defect Cases by Number of Defects per Case 29 3.2 Birth Defect Cases by Infant Sex 29 3.3 Birth Defect Cases by Birthweight 29 3.4 Birth Defect Cases by Gestational Age 30 3.5 Birth Defect Cases by Plurality 30 3.6 Perinatal Mortality Associated with Birth Defect Cases 31 4. Birth Defect Cases by Selected Maternal Factors 4.1 Birth Defect Cases by Maternal Age 33 4.2 Birth Defect Cases by Maternal Country of Birth 33 4.3 Birth Defect Cases by Department of Human Services Regions 34 4.4 Birth Defect Cases by Aboriginality 34 4.5 Birth Defect Cases by Marital Status 35 4.6 Birth Defect Cases by Parity 35

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5. Major Birth Defects 5.1 Anencephaly 37 5.2 Spina Bifida 40 5.3 Encephalocele 43 5.4 Microcephalus 46 5.5 Hydrocephalus 49 5.6 Transposition of Great Vessels 52 5.7 Tetralogy of Fallot 55 5.8 Ventricular Septal Defect 58 5.9 Hypoplastic Left Heart Syndrome 61 5.10 Coarctation of Aorta 64 5.11 Cleft Palate 67 5.12 Cleft Lip 70 5.13 Cleft Lip and Palate 73 5.14 Oesophageal Atresia and/or Stenosis 76 5.15 Anorectal Atresia and/or Stenosis 79 5.16 Hypospadias 82 5.17 Renal Agenesis and Dysgenesis 85 5.18 Cystic Kidney Disease 88 5.19 Obstructive Defects of Renal Pelvis 91 5.20 Congenital Dislocation of Hip 94 5.21 Limb Reduction Defects 97 5.22 Diaphragmatic Hernia 100 5.23 Exomphalos 103 5.24 Gastroschisis 106 5.25 Trisomy 21 109 5.26 Trisomy 13 112 5.27 Trisomy 18 115 References 119 Appendix A: Publications, January 1999 July 2000 120 Appendix B: Exclusions 122 Appendix C: Routine Data Items in the Birth Defects Register 125 Appendix D: Denominator Figures for Tables on Selected Maternal and 127 Infant Characteristics for Twenty Seven Selected Defects Appendix E: Department of Human Services - Rural Regions 127 Department of Human Services- Metropolitan Region Appendix F: Allocation of Postcodes to Current LGA boundaries 129

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Acknowledgments

This report would not have been possible without the assistance of:

• Midwives in Victoria who completed and returned the Perinatal Morbidity Statistics Forms

• Maternal and Child Health Nurses who completed and returned the Birth Defect Notification forms

• Health Information Managers at all hospitals with maternity services and, in particular, those at hospitals with paediatric services

• Women’s and Children’s Network - Health Information Management, Cardiology Unit (Dr Jim Wilkinson), Information Technology (Ron Burnett), Ultrasound Department, Genetics Clinic and Cytogenetics Laboratory

• Monash Medical Centre - Health Information Management, Ultrasound Department and Genetics Clinic, Information Technology

• Genetic Health Services Victoria

• Melbourne Pathology and Cytogenetic Services Victoria

• Dr Catherine Rose, Consultant Medical Officer, Perinatal Data Collection Unit

• Members of the Consultative Council on Obstetric and Paediatric Mortality and Morbidity

• Staff of the Perinatal Data Collection Unit

We thank all of the above people for their contributions.

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Abbreviations a/s atresia/stenosis AIHW Australian Institute of Health and Welfare anom anomalies ASD atrial septal defect BDR Birth Defects/Congenital Malformations Register CDH congenital dislocation of hip chrom chromosomal CI confidence interval CMR Birth Defects/Congenital Malformations Register cns central nervous system COA coarctation of aorta desc described dev developmental df degrees of freedom dysgen dysgenesis electr electrolyte end. endocrine g grams HLHS hypoplastic left heart syndrome inc includes ICD International Classification of Diseases LGA Local Government Area MCH Nurse Maternal & Child Health Nurse metab metabolic MHW Mercy Hospital for Women MMC Monash Medical Centre nec not elsewhere classified NND neonatal death NPSU National Perinatal Statistics Unit nutri nutritional p probability PDA patent ductus arteriosus PDCU Perinatal Data Collection Unit pns peripheral nervous system RCH Royal Children’s Hospital red reduction RR relative risk RWH Royal Women’s Hospital s/insuff stenosis/insufficiency SB stillbirth spec specified sternocleido sternocleidomastoid TGV transposition of great vessels TOP termination of pregnancy trans translocation udt undescended testis unspe unspecified VSD ventricular septal defect

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Definitions (as used in the BDR Report)

A birth defect is a structural or functional abnormality that is present at birth, resulting from abnormal development during pregnancy.

Birth defect cases refers to the number of liveborn or stillborn infants, or terminations before 20 weeks affected by at least one birth defect.

Birth prevalence has as the denominator, the number of still and livebirths at and after 20 weeks gestation. Overall prevalence includes terminations of malformations before 20 weeks gestation.

Isolated anomalies are defined as cases with a single condition or a single condition associated with one or more minor anomalies listed on the exclusion list (Appendix B), but which have been included periodically throughout the history of the BDR.

Livebirth is the complete expulsion or extraction from its mother of a baby of at least 20 weeks gestation or, if gestation is unknown, weighing at least 400g who, after being born, breathes or shows any evidence of life such as a heartbeat.

Neonatal death refers to a death occurring within 28 days of livebirth in an infant whose gestation was at least 20 weeks or, if gestation is unknown, weighing at least 400g.

Perinatal death is a stillbirth or neonatal death.

Stillbirth is the complete expulsion or extraction from its mother of a baby of at least 20 weeks gestation or, if the gestation is unknown, weighing at least 400g who did not, at any time after delivery, breathe or show any evidence of life such as a heartbeat.

Termination of pregnancy refers to an induced abortion before 20 weeks gestation.

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Highlights • In 19992000, there were 4,498 babies born with a birth defect at or after 20 weeks gestation.

Another 578 were identified as terminations of pregnancy before 20 weeks gestation. This gives an overall prevalence of a birth defect of 405/10,000 or 4%. Pregnancy termination before 20 weeks occurred for 11.4% of cases.

• Overall birth defect prevalence is gradually increasing which may reflect a combination of factors such as improved ascertainment and increased numbers of older women having babies. A significant increase in prevalence since 1983 has been seen for many conditions, but the greatest increases have been in obstructive defects of the renal pelvis, hypospadias, Trisomy 21, Trisomy 18, cystic kidney disease, hydrocephalus and gastroschisis. The only significant declines have been for neural tube defects (anencephaly, spina bifida & encephalocele), coarctation of aorta, and congenital dislocated hip. Significant annual decreases in 2000 were seen for diaphragmatic hernia and exomphalos.

• The four most common birth defects for the period 19992000 were the same as in previous years, but the order has changed with obstructive defects of the renal pelvis the most common, followed by hypospadias, ventricular septal defect (VSD) and congenital dislocation of the hip.

• There are some significant gender differences in birth prevalence with males generally at higher risk than females (4.4% compared with 3.3%). Birth defects significantly associated with males are often renal (anorectal atresia, renal agenesis/dysgenesis, obstructive defects of renal pelvis). Males are also at increased risk of cleft lip and palate, limb reduction defects and Down syndrome, while females have an increased risk for encephalocele, transposition of great vessels, cleft palate and congenital dislocation of the hip.

• Twins are more at risk of having a birth defect than singletons (5.8% compared with 4.0%). A number of birth defects are seen more often in twins, especially oesophageal atresia, but also hydrocephalus, VSD, anorectal atresia, hypospadias and cystic kidney disease.

• Women aged 35 years or more (18.7% of women having babies in the period 19992000) comprise 22.5% of all women who have a pregnancy affected by a birth defect for this same period. This over-representation of older women amongst those who have babies with birth defects is borne out by the data showing that the prevalence of a birth defect is 4.4% for women 35-39 years and 7% for women 40 years and over.

• Even when cases with a chromosome abnormality (Trisomies 21, 18 or 13, and their accompanying birth defects) are excluded, there is still an overrepresentation of older women having babies with birth defects: 19.5% are 35 years or over. Other birth defects significantly associated with advanced maternal age are VSD, exomphalos and cleft lip and palate.

• Teenage mothers also have an overall increased risk of having a baby with a birth defect (4.7%). They have a significantly increased risk of having babies with anorectal atresia and gastroschisis, the latter association having been recognised since the early 1990s.

• Women from the Middle East are significantly more likely to have a baby with a birth defect (in particular microcephaly, hydrocephaly or obstructive defect of the renal pelvis) compared with Australian- or Asian- born women. This is not related to advanced maternal age and may reflect genetic factors. Asian-born women are at reduced risk of having babies with spina bifida, hypospadias, renal agenesis or dysgenesis and congenital hip dislocation, but are at increased risk of Trisomy 18.

• Women from Rural Regions (grouped) have a statistically significant decreased likelihood of having a baby with a birth defect when compared to Metropolitan Regions (grouped) (RR 0.94, 96% CI 0.89-0.98, p<0.0001). This is a small decrease and may relate to ascertainment issues as much as a biological risk.

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• The prevalence of birth defects in 19992000 in pregnancies of women recorded as Koori on the Perinatal Morbidity Statistics(PMS) Forms is not significantly different than for those recorded on the PMS Forms as non-Koori (RR 0.82, 95% CI 0.54 – 1.22, p=0.32).

• There has been a significant decline in overall prevalence of all three neural tube defects (NTDs) observed since 1995. This almost certainly represents the impact of better nutritional intake of folate by women pre- and post- conception, a known primary preventive measure for NTDs. We have not observed the full potential impact of folate because many women are not having enough folate fortified food nor aware of the need to take this supplement before conception and many pregnancies are unplanned. The 19992000 data on overall prevalence of these birth defects in pregnancy was 1/2,500 for anencephaly, 1/1,350 for spina bifida, 1/5,000 for encephalocele or 1 in 758 for any neural tube defect. This compares with a higher risk of 1 in 592 between 19951998, and represents a 28% reduction in risk.

• The number of cases reported with obstructive defects of the renal pelvis continues to increase annually. This is due to increased detection by ultrasound during pregnancy. Follow up information on the babies diagnosed in utero is obtained where possible at the time of data collection (after birth) and longer term clinical evaluation of prenatal diagnoses of these infants is underway in Victoria.

• From 19831994, 62% of the cases of Trisomy 21 were found in pregnancies of women who were less than 35 years of age, but in 19992000, only 42% were identified in women less than 35 years. This shift in proportion and the overall increase in prevalence is due to a number of reasons: 1) the increasing number of older women having babies 2) detection in early pregnancy, using ultrasound and maternal serum screening, of affected fetuses, that would once have spontaneously aborted and never entered the statistics.

• Despite the increase in prenatal detection of fetuses with Trisomy 21, there has been no marked decrease in the number of liveborn babies with this condition since 1995. This may be related to an increasing number of older pregnant women not having prenatal testing.

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1. Introduction

1.1 Background With the decline of mortality and morbidity in children from other causes (eg infection), birth defects are now more prominent as a serious health hazard of childhood. Approximately 4% of Victorian babies are born each year with a birth defect and they contribute substantially to the number of perinatal deaths and morbidity in our community.

History

In 1979 the Commonwealth Government agreed in principle to collect more information about births and birth defects. It was decided that the States would be responsible for setting up their own systems and the Commonwealth would establish a National Perinatal Statistics Unit, to collate information from all the states and provide an overall picture. The Victorian Perinatal Data Collection Unit (PDCU), established under the Health Act of 1958, operates under the aegis of the Consultative Council on Obstetric and Paediatric Mortality and Morbidity (the Council). One of the fundamental purposes of the PDCU was the establishment and maintenance of a Birth Defects/Congenital Malformations Register (BDR). The ongoing maintenance of the BDR is enshrined in the legislation pertaining to the PDCU and is an ongoing function of the PDCU.

Each year birth defect data are presented in a section of the Annual Report of the Council (1) . In addition, the data are used in a number of ways, including research, service planning, consumer reports, and policy development (Appendix A). The main purposes of the BDR are listed below.

1.2 Purposes of the BDR The purposes of this state-wide population based surveillance system are to:

1. determine how often birth defects are occurring in Victoria and identify changing health

service needs (prevalence and survival data),

2. give statistical information to organisations responsible for planning and providing health care facilities for those with birth defects, or who provide information to those concerned about having a baby with a birth defect,

3. provide information for epidemiological research to increase knowledge of aetiology and preventability of birth defects,

4. assess effectiveness of primary prevention and screening programs for birth defects,

5. respond to community and health service provider concerns about perceived clusters or changes in frequency of birth defects.

1.3 Inclusion Criteria A notifiable birth defect is defined as an abnormality in body structure, function or chemistry, present at birth, but not necessarily noticed at birth. The BDR collects information on chromosome abnormalities, inborn errors in metabolism, haematological disorders, congenital infections, neoplasms, and developmental delay (associated with a syndrome). There are certain isolated minor malformations (such as inguinal hernia, and hydrocele) that are not notifiable and these exclusions are listed in Appendix B.

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The BDR also collects data on all birth defects for livebirths, stillbirths and terminations of pregnancy occurring since January 1, 1982, irrespective of the age at diagnosis, up to 15 years of age.

In this report, information is included on cases notified to the BDR by June, 2002. Certain isolated minor defects such as undescended testes (>=37 weeks gestation ), vesico-ureteric reflux, and all conditions listed in the Exclusions List (Appendix B) have been excluded from this report. This may account for some of the differences between reports from some other States, where higher birth defect prevalence arises from the inclusion of such minor malformations.

1.4 Sources of Notification The BDR is a voluntary notification system. Data are obtained from multiple sources. Table 1.1 details the number of notifications of birth defect cases for 19992000 births. The number of notifications exceeds the number of cases due to multiple reporting of cases from different sources.

For the period 19992000 there were 7,169 notifications for a total of 5,076 cases. This approximates to 1.4 notifications per case.

Table 1.1 Sources of Notification, 19992000

Notification Source Number Percent(%) PDCU - perinatal form 3,762 52.5 Hospital listing 1,945 27.1 Perinatal Death Certificate 375 5.2 Autopsy Report 210 2.9 Cytogenetics Report 491 6.7 Maternal and Child Health Nurse 340 4.7 Other Professional 38 0.5 Other (e.g. parent) 7 0.1 Unknown 1 0.0 Total 7,169 100.0

1.5 Data Items All notifications of birth defects (excluding terminations of pregnancy before 20 weeks and interstate births) are linked to the Perinatal Morbidity Statistics Form to obtain an obstetric history for each case. Midwives complete this form as part of the mandatory notification system to the PDCU for every birth in Victoria (see Definitions). The data items routinely maintained on the BDR are listed in Appendix C. Further data items are available for each case of 20 weeks gestation or more from the Perinatal Morbidity Statistics Form, as required.

1.6 Data Quality Over the years the data quality of the BDR has been assessed by validation studies (3,4,5). The first, conducted in 1986, discovered that the proportion of birth defects notified to the BDR improved from 35% to 48% during the period 19821985. The second study, conducted in 1993, also reported a marked improvement in notification rates from 50% to 86% during the period 19891992. The most recent study done in 2001 (as yet unpublished) noted again further

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improvement in notification to 88%. However, there is always room for improvement, and ascertainment of all early terminations remains difficult.

Since 1992 considerable time and effort has been expended in improving the quality of the data in the BDR. The Register has been updated from hospital inpatient listings from the Royal Children’s Hospital (RCH) detailing all children born since 1982 who have subsequently been admitted to the RCH with a birth defect. We have also obtained listings of all children born since 1982 who have visited the RCH Cardiology Unit and Genetic Health Services Victoria Metabolic Clinic, either as an inpatient or outpatient. This procedure has also been adopted for Monash Medical Centre where the inpatient listings date back to 1992.

1.7 Confidentiality There is a strict policy in place to guide use of the data held in the BDR for statistical and research purposes. The data are held in a secure place, with any hard copy information under lock and key and password protected on stand alone computers (non-networked). Foremost consideration is that the release of data by the Council will not endanger the confidentiality of the information. Human Research Ethics Committee approval must be obtained for research projects that encompass use of birth defect data and there is no approval given for contact with the individual or parent/guardian without permission from the relevant physician, who may or may not be the notifier of the birth defect to the Register. Identifiable data are not provided in any report.

1.8 Explanatory Notes

Defects versus Cases Section 2 describes each individual birth defect (defect rate). Sections 3 & 4 describe birth defect cases (case rate) - the number of liveborn or stillborn infants affected by at least one birth defect. Thus, the number of birth defects exceeds the number of cases.

Defect rate = Number of records of a particular birth defect X 10000 Total number of livebirths, stillbirths and TOPs < 20 weeks Case rate = Number of livebirths, stillbirths & TOPs< 20 weeks with one or more birth defect X 10000 Total number of livebirths and stillbirths and TOPs < 20 weeks

Classification of Diseases Conditions have been classified using the British Paediatric Association Classification of Diseases - Perinatal Supplement, compatible with International Classification of Diseases - 9th revision.

With Syndromes it is the practice of the PDCU to code the syndrome and all of its manifestations.

Births and Confinements There is an important difference between the number of births and the number of confinements . Confinement is defined as the final phase of pregnancy during which labour and birth occur. Any one confinement can result in more than one birth, such as is the case with twins. Tables related to infant characteristics use births as the denominator. Tables related to maternal factors

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use confinements as the denominator. This differs from the first report (6) where only births were used as the denominator for both infant and maternal characteristics.

See Appendix D for comparison data for the denominator figures for infant and maternal characteristics for twenty-seven selected defects.

Maternal Country of Birth For the purposes of this report we have separated women born in Asia from those born in the Middle East. In the first report (6 ) these women were combined in one category called “Asia including Middle East”.

Twenty-Seven Selected Defects

As in our previous reports (2,6), this report includes detailed information on twenty-seven selected defects that are either “lethal, have significant consequences for surviving children and their families, or are relatively common” (7).

1.9 Terminations of Pregnancy Termination of pregnancy refers to an induced abortion before 20 weeks gestation. If there is an induced abortion at 20 weeks or more, or if the gestation is unknown and the birthweight is 400 grams or more, it is required to be registered as a birth and is classified as a stillbirth, or occasionally a neonatal death, in the PDCU and the BDR.

Notification of terminations for birth defects began in 1986. While the capture of these data in the early years was very incomplete, each subsequent year has shown a marked improvement in ascertainment of cases. There has also been an increase in the number of terminations because of the increased use of prenatal diagnosis (1).

Since 1986 a PDCU staff member has been responsible for reviewing the medical records of all women who have had a termination of pregnancy for birth defect(s) at both Monash Medical Centre and the Royal Women’s Hospital. A letter is sent to all other hospitals with maternity beds to obtain the same relevant information. This procedure has an ICD code which enables extraction of these specific records.

1.10 Statistics For each rate, a 95% Poisson confidence interval (if number of cases < 400) or a 95% Binomial confidence interval (if number of cases >= 400) has been calculated. This allows for comparisons between rates to be made and significant differences to be recognised; if the confidence intervals do not overlap, then the rates will be significantly different at the 5% level (p <0.05). Chi square for linear trend has been calculated using Epi Info Version 6.1. Relative risks in sections 3 and 4 have also been calculated using Epi Info.

1.11 Regional Variations Victoria is divided into a number of Health Regions for planning and policy purposes. Between 19832000 changes have occurred in Regional boundaries at least three times. Therefore any conclusions drawn from differences in the prevalence of birth defects between Regions should be made with due consideration of the Regional boundary changes and allocation of postcodes. These are detailed in the previous report (2).

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1.12 Previous Reports This latest report on birth defects in 1999 and 2000 updates the previous 19831998 Birth Defects in Victoria Report (2), which also provides an overview of key maternal, and infant factors associated with birth defects. That report in turn provided supplementary information to a previous report, Congenital Malformations in Victoria 19831994 (6).

Differences with the Birth Defects in Victoria 19831998 (2) This report has excluded all cases which have any isolated conditions listed on the Exclusions List (Appendix B). These cases were not excluded in previous reports (2,6) and therefore the prevalence of birth defects may have decreased by up to 0.2% when compared with the annual prevalence in the earlier years of reporting.

Differences with the Annual Report (s) of the Consultative Council on Obstetric and Paediatric Mortality and Morbidity (1) Many differences in prevalence data exist between this current report and the Annual Report(s) of the Consultative Council on Obstetric and Paediatric Mortality and Morbidity. This can primarily be attributed to the time period being reported. The BDR continues to include data on children who are reported with a birth defect up until the age of 15 years. Therefore new cases are being added (or sometimes deleted) each year. Each report is current at the time of publication, but is never “complete”.

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2. Summary Tables

2.1 Birth Defects by Year, 1983—2000 The combined birth prevalence of birth defects over 18 years is 346.0/10,000 or 3.5%. The increase until 1990 probably reflects improving ascertainment, but the fluctuations since 1990 are more likely to reflect “true prevalence”, as the methods of ascertainment since then have been the same. From 19951998 the overall prevalence was 402.1/10,000 (4.0%) and for 19992000 the overall prevalence was 404.8/10,000 (4.0%).

Table 2.1 Birth Defects by Year, 1983—2000

Year Total Births, 20 Weeks and

Later

Defects, 20 Weeks and

Later

Defects Before 20 Weeks

(Terminations)

N/10,000 Pregnancies

(including Terminations)

%

1983 60,628 1,637 2 270.3 2.7 1984 60,737 1,659 10 274.7 2.7 1985 61,189 1,569 17 259.1 2.6 1986 61,253 1,571 80 269.2 2.7 1987 61,566 1,590 55 267.0 2.7 1988 63,666 1,828 103 302.8 3.0 1989 64,255 1,934 122 319.4 3.2 1990 66,878 2,133 134 338.3 3.4 1991 65,248 2,222 140 361.2 3.6 1992 66,305 2,283 152 366.4 3.7 1993 64,737 2,233 204 375.3 3.8 1994 64,932 2,315 250 393.5 3.9 1995 63,717 2,425 255 418.9 4.2 1996 62,951 2,224 272 394.8 3.9 1997 62,308 2,211 298 400.8 4.0 1998 62,091 2,180 278 394.1 3.9 1999 62,689 2,395 295 427.1 4.3 2000 62,564 2,103 283 379.7 3.8 Total 1,137,714 36,512 2,950 346.0 3.5

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2.2 Comparison of Prevalence of Birth Defects, 19831994, 19951998 and 19992000.

Table 2.2 Comparison of Prevalence of Birth Defects, 19831994, 19951998 and 19992000

Defect Number (19831994)

Rate* Number (19951998)

Rate* Number (19992000)

Rate*

Total births + TOPs 762,705 252,158 125,831 Anencepahly 401 5.3 185 7.3 49 3.9 Spina Bifida 649 8.5 205 8.1 93 7.4 Encephalocele 149 2.0 38 1.5 25 2.0 Microcephalus 241 3.2 69 2.7 28 2.2 Hydrocephalus 497 6.5 224 8.9 131 10.4 Transposition of Great Vessels 372 4.9 134 5.3 68 5.4 Tetralogy of Fallot 256 3.4 97 3.8 60 4.8 Ventricular Septal Defect 2,049 26.9 734 29.1 406 32.3 Hypoplastic Left Heart Syndrome 205 2.7 63 2.5 43 3.4 Coarctation of Aorta 447 5.9 101 4.0 41 3.3 Cleft Palate 556 7.3 196 7.8 95 7.5 Cleft Lip 298 3.9 83 3.3 60 4.8 Cleft Lip and Palate 504 6.6 157 6.2 88 7.0 Oesophageal Atresia and/or Stenosis

274 3.6 103 4.1 38 3.0

Anorectal Atresia and/or Stenosis 292 3.8 135 5.4 42 3.3

Hypospadias 1,848 24.2 809 32.1 399 31.7 Renal Agenesis and Dysgenesis 368 4.8 165 6.5 89 7.1

Cystic Kidney Disease 302 4.0 167 6.6 92 7.3 Obstructive Defects of Renal Pelvis

804 10.5 705 28.0 520 41.3

Congenital Dislocation of Hip 2,245 29.4 657 26.1 329 26.1 Limb Reduction Defects 461 6.0 181 7.2 78 6.2 Diaphragmatic Hernia 253 3.3 104 4.1 41 3.3 Exomphalos 218 2.9 97 3.8 34 2.7 Gastroschisis 100 1.3 65 2.6 39 3.1 Trisomy 21 1,195 15.7 525 20.8 322 25.6 Trisomy 13 108 1.4 62 2.5 36 2.9 Trisomy 18 266 3.5 156 6.2 78 6.2 *Rate = n/10,000 births plus TOPs

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2.3 Order of Prevalence of Twenty Seven Selected Birth Defects, 19992000 The following table shows the order of prevalence of twenty-seven selected defects presented in section five of this report for 1999—2000. These are the defects adopted by the International Clearinghouse for Birth Defects Monitoring System and are those reported by the National Perinatal Statistics Unit (7).

Table 2.3 Order of Prevalence of Twenty Seven Selected Birth Defects, 1999—2000

Anomaly n/10,000 1 in x number of births + TOPs

Obstructive Defects of Renal Pelvis 41.3 242 Hypospadias 31.7 315 Ventricular Septal Defect 30.2 331 Congenital Dislocated Hip 26.1 383 Trisomy 21 25.6 391 Hydrocephalus 10.4 962 Cleft Palate 7.5 1,333 Spina Bifida 7.4 1,351 Cystic Kidney 7.3 1,370 Cleft Lip and Palate 7.1 1,408 Renal Agenesis and Dysgenesis 7.1 1,408 Limb Reduction Defects 6.2 1,613 Trisomy 18 6.2 1,613 Transposition of Great Vessels 5.4 1,852 Tetralogy of Fallot 4.8 2,083 Cleft Lip 4.8 2,083 Anencephaly 3.9 2,564 Hypoplastic Left Heart Syndrome 3.4 2,941 Anorectal Atresia and/or Stenosis 3.3 3,030 Diaphragmatic Hernia 3.3 3,030 Coarctation of Aorta 3.3 3,030 Gastroschisis 3.1 3,226 Oesophageal Atresia and/or Stenosis 3.0 3,333 Trisomy 13 2.9 3,448 Exomphalos 2.7 3,704 Microcephalus 2.2 4,545 Encephalocele 2.0 5,000

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2.4 Summary of Patterns for Twenty-Four Selected Defects, 19992000

The table below reflects the associations with other birth defects for twenty-four selected defects: that is, whether they are isolated conditions, or associated with chromosomal anomalies or occur as multiple same system (eg. two or more cardiac defects) or multiple different system defects (eg. cleft lip and ventricular septal defect).

Table 2.4 Summary of Patterns of Birth Defects for Twenty-Four Selected Defects, 1999—2000

Anomaly Total % Isolated %

Chromosomal

% Other (Multiple Same System &

Multiple Different Systems)

Anencephaly 49 75.5 0.0 24.5 Spina Bifida 93 72.0 2.2 25.8 Encephalocele 25 52.0 0.0 48.0 Microcephalus 28 14.3 25.0 60.7 Hydrocephalus 131 42.7 15.3 42.0 Transposition of Great Vessels 68 7.4 7.4 85.3 Tetralogy of Fallot 60 36.7 10.0 53.3 Ventricular Septal Defect 406 42.6 14.0 43.3 Hypoplastic Left Heart Syndrome 43 25.6 18.6 55.9 Coarctation of Aorta 41 17.1 19.5 63.4 Cleft Palate 95 60.0 9.5 30.5 Cleft Lip 60 81.7 8.3 10.0 Cleft Lip & Palate 88 64.8 10.2 25.0 Oesophageal Atresia and/or Stenosis 38 36.8 7.9 55.3 Anorectal Atresia and/or Stenosis 42 26.2 16.7 57.2 Hypospadias 399 87.7 1.0 11.3 Renal Agenesis/Dysgenesis 89 36.0 10.1 53.9 Cystic Kidney 92 48.9 3.3 47.8 Obstructive Defects of Renal Pelvis 520 70.8 2.1 26.1 Congenital Dislocated Hip 329 92.1 0.9 7.0 Limb Reduction Defects 78 39.7 6.4 53.9 Diaphragmatic Hernia 41 58.5 14.6 26.8 Exomphalos 34 35.3 32.4 32.4 Gastroschisis 39 74.4 2.6 23.1

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2.5 Birth Defects by Four Digit Code, 1999—2000 The following figures refer to individual birth defects, not cases.

Table 2.5 Birth Defects by Four Digit Code, 1999—2000

Codes@ Defects Number N/10,000 740* Anencephalus & Similar Anomalies 56 4.5 7400# Anencephalus 55 4.4 7401 Craniorachischisis 1 0.1 7402 Iniencephaly 0 0.0 741* Spina Bifida 95 7.5 742 Other Nervous System (NS) 378 30.0 7420 Encephalocele 25 2.0 7421 Microcephalus 28 2.2 7422 Brain Reduction 83 6.6 7423* Hydrocephalus 132 10.5 7424-9 Other 90 7.2 330-7 Hereditary & Degenerative Diseases of CNS 14 1.1 343-9 Cerebral Palsy 2 0.2 340-2/3499 Other Disorders of CNS 1 0.1 350-9 Disorders of Peripheral N S 3 0.2 743 Eye 72 5.7 7430 Anophthalmos 4 0.3 7431 Microphthalmos 7 0.6 7432 Buphthalmos 5 0.4 74330-1/3-9 Other Lens 1 0.1 74332 Cataract 17 1.4 7434-9 Other 38 3.0 744 Ear, Face & Neck 97 7.7 7440 Ear-Affecting Hearing 6 0.5 74400 Auditory Canal 3 0.2 74401 Absent Auricle 0 0.0 74402-9 Other 3 0.2 7441-3 Other Ear 64 5.1 7444-9 Face & Neck 27 2.1 745 Bulbus Cordis & Cardiac Septal Closure 1,038 82.5 7450 Common Truncus 14 1.1 7451* Transposition of Great Vessels 71 5.6 7452 Tetralogy of Fallot 60 4.8 7453 Common Ventricle 12 1.0 7454* Ventricular Septal Defect 406 32.3 7455 Atrial Septal Defect 409 32.5 7456 Endocardial Cushion 58 4.6 7457-9 Other 8 0.6 @ Codes according to the British Paediatric Association Classification of Diseases Supplement to ICD – 9th Revision

* It is possible for one case to have two or more conditions within this code range. Therefore the number of birth defects may exceed the number of cases.

# Anencephalus includes absence of brain, acrania, anencephaly and hemianencephaly.

continued next page

22

Table 2.5 Birth Defects by Four Digit Code, 19992000 (cont.)

Codes Defects Number N/10,000 746 Other Heart 445 35.4 425 Cardiomyopathy 5 0.4 426 Conduction Disorder 3 0.2 7460 Pulmonary Valve 99 7.9 74600 Atresia 20 1.6 74601 Stenosis 74 5.9 74602-9 Other 5 0.4 7461 Tricuspid Atresia/Stenosis 76 6.0 7462 Ebstein Anomaly 3 0.2 7463-4 Aortic Valves Stenosis/Insufficiency 36 2.9 7465-6 Mitral Stenosis/Insufficiency 33 2.6 7467 Hypoplastic Left Heart Syndrome 43 3.4 7468 Other Specified 110 8.7 7469 Unspecified 37 2.9 747 Circulatory 466 37.0 7470 Patent Ductus Arteriosus 203 16.1 7471 Coarctation of Aorta 41 3.3 7472 Other Aorta 44 3.5 7473 Pulmonary Artery 59 4.7 7474 Great Veins 34 2.7 7475 Single Umbilical Artery 2 0.2 7476 Peripheral Vascular 5 0.4 7478 Other Specified 75 6.0 7479 Unspecified 2 0.2 748 Respiratory 195 15.5 7480 Choanal Atresia 24 1.9 7481 Other Nose 21 1.7 7482-3 Larynx/Trachea//Bronchus 38 3.0 7484-6 Lung 108 8.6 7488-9 Other Respiratory 4 0.3 749* Cleft Palate/Lip 247 19.6 7490 Cleft Palate 98 7.8 7491 Cleft Lip 60 4.8 7492 Cleft Lip & Palate 88 7.0 750 Upper Alimentary Tract 61 4.8 7503 TOF Oesophageal Atresia/Stenosis 38 3.0 7501-2/4-9 Other 22 1.7 751 Other Digestive 271 21.5 7510 Meckels Diverticulum 5 0.4 7511 Small Intestine Atresia/Stenosis 44 3.5 75110 Duodenal Atresia/Stenosis 21 1.7 75111 Jejunal Atresia/Stenosis 9 0.7 75112 Ileal Atresia/Stenosis 7 0.6 75119 Unspecified Atresia/Stenosis 7 0.6 7512* Large Intestine Rectal Anal Atresia/Stenosis 47 3.7 75120 Large Intestine Atresia/Stenosis 3 0.2 75121-2 Rectal Atresia/Stenosis 7 0.6 75123-4 Anal Atresia/Stenosis 37 2.9 * It is possible for one case to have two or more conditions within this code range. Therefore the number of birth defects may exceed the number of cases. Continued next page

23


Codes Defects Number N/10,000 7513 Hirschsprung’s Disease 29 2.3 7514 Intestinal Fixation 29 2.3 7515-9 Other Digestive 98 7.8 524-579 Other 19 1.5 752 Genital Organs 636 50.5 7520-1 Ovaries/Fallopian etc 9 0.7 7522-3 Uterus 3 0.2 7524 Cervix/Vagina/ External Genitalia 12 1.0 7525* Undescended Testes 66 5.2 75260/3-5 Hypospadias 399 31.7 75261 Epispadias 12 1.0 75262 Chordee 49 3.9 7527 Indeterminate Sex 17 1.4 7528 Other Specified 66 5.2 7529 Unspecified 3 0.2 753 Urinary 967 76.8 7530 Renal Agenesis/Dysgenesis 89 7.1 75300 Bilateral 42 3.3 75301 Unilateral 47 3.7 7531# Cystic Kidney Disease 92 7.3 75311-3 Polycystic 32 2.5 75316 Multicystic 47 3.7 75310/4/8 Other 13 1.0 7532# Obstructive Defects Renal Pelvis/Ureter 636 50.5 75320 Hydronephrosis 455 36.2 75321-9 Other 104 8.3 75330/1/3-9 Other Specified Kidney Disorders 58 4.6 7533 Horseshoe Kidney 19 1.5 7534 Other Specified Disorders of Ureter 31 2.5 7535 Exstrophy of Bladder 6 0.5 7536 Urethra Bladder Neck Atresia/Stenosis 38 3.0 7537 Urachus 0 0.0 7538 Other Bladder/Urethra 28 2.2 7539 Unspecified 10 0.8 592-608 Other 37 2.9 754 Certain Musculoskeletal 769 61.1 7540 Of Skull, Face & Jaw 25 2.0 7541 Of Sternocleidomastoid 1 0.1 7542 Of Spine 7 0.6 75430 Congenital Dislocated Hip 329 26.1 75431-2 Other Hip 13 1.0 7544 Genu Recurvatum/Bowing 3 0.2 7545-7 Of Feet 388 30.8 7548 Other 3 0.2 * Undescended testes in term babies is included in BDR, but isolated cases have been excluded for the purposes of this report as a minor malformation. This figure refers to cases of undescended testes which are not isolated but occur with other malformations. # It is possible for one case to have two or more conditions within this code range. Therefore the number of birth defects may exceed the number of cases. continued next page

24


Codes Defects Number N/10,000 755* Limbs 485 38.5 7550 Polydactyly 127 10.1 7551 Syndactyly 107 8.5 7552 Reduction Deformities Upper Limb 55 4.4 7553 Reduction Deformities Lower Limb 44 3.5 7554 Reduction Deformities Unspecified Limb 3 0.2 7555 Other Upper Limb 54 4.3 7556 Other Lower Limb 70 5.6 75580 Arthropgryposis Multiplex Congenita 15 1.2 75581-8 Other Specified 8 0.6 7559 Unspecified 2 0.2 756 Other Musculoskeletal 346 27.5 7560 Skull, Face & Bones 111 8.8 75600 Craniosynostosis 40 3.2 75601-2/4-9 Other 55 4.4 75603 Pierre Robin Syndrome 16 1.3 7561 Spine 32 2.5 7562-3 Ribs & Sternum 20 1.6 7564 Chondrodystrophy 25 2.0 75643 Achondroplasia 3 0.2 75644 Other Dwarfing 4 0.3 75640-2/5-9 Other 18 1.4 7565 Osteodystrophies 20 1.6 75650 Osteogenesis 12 1.0 75651-9 Other 8 0.6 7566 Diaphragm 44 3.5 75660/2-9 Other 3 0.2 75661 Diaphragmatic Hernia 41 3.3 7567 Abdominal Wall 80 6.4 75670 Exomphalos 34 2.7 75671 Gastroschisis 39 3.1 75672-9 Other 7 0.6 7568 Other Specified of Muscle/ Tendon/ Fasica/ 10 0.8 7569 Unspecified 4 0.3 757 Integument 84 6.7 7571 Icthyosis Congenita 7 0.6 7572 Dermatoglyphic Anomalies 1 0.1 7573 Other Specified Anomalies Skin 63 5.0 7574 Specified Anomalies of Hair 1 0.1 7575 Specified Anomalies of Nails 4 0.3 7576 Specified Anomalies of Breast 3 0.2 7578 Other Specified Anomalies of Integument 2 0.2 7579 Unspecified 3 0.2 # It is possible for one case to have two or more conditions within this code range. Therefore the number of birth defects may exceed the number of cases. continued next page

25


Codes Defects Number N/10,000 758 Chromosomal 678 53.9 7580 Trisomy 21 314 25.0 7581 Trisomy 13 36 2.9 7582 Trisomy 18 78 6.2 7583 Autosomal Deletion 45 3.6 7585 Other Autosomal 82 6.5 7586 Turner’s Syndrome 51 4.1 7587 Klinefelter’s Syndrome 19 1.5 7588 Other Sex Chromosomes 21 1.7 7589 Unspecified 32 2.5 759 Other 181 14.4 7590 Spleen 21 1.7 7591 Adrenal Gland 13 1.0 7592 Other Endocrine Gland 27 2.1 7593 Situs Inversus 9 0.7 7594 Conjoined Twins 2 0.2 7595 Tuberous Sclerosus 6 0.5 7596 Harmartoses NEC 6 0.5 7597 Multiple so described 7 0.6 7598 Other Specified Syndromes 76 6.0 7599 Unspecified 14 1.1 Other 70 5.6 7602-7611/2 Maternal Conditions 1 0.1 76070 Fetal Hydantoin Syndrome 0 0.0 76076 Fetal Alcohol Syndrome 0 0.0 7710-2 Congenital Infection 14 1.1 77121 Toxoplasmosis 1 0.1 77119 Cytomegalovirus 13 1.0 7780 Hydrops Fetalis (Non-Immune) 55 4.4 140-239 Neoplasms 55 4.4 140-208 Malignant 6 0.5 210-229 Benign 41 3.3 22809 Haemangioma 3 0.2 22819 Cystic Hygroma 36 2.9 2100-2279 Other 2 0.2 235-9 Uncertain Behaviour 8 0.6 240-279 Endocrine/Nutritional/Metabolic 119 13.5 2439 Congenital Hypothyroidism 28 2.2 240-2/4-6 Other Thyroid Gland 0 0.0 250-9 Other Endocrine Glands 10 0.8 260-9 Nutritional Deficiencies 0 0.0 2701 Phenylketonuria 14 1.1 2700/2-9 Other Disorders of Amino-Acid Metabolism 4 0.3 271 Of Carbohydrate Metabolism 8 0.6 272 Of Lipid Metabolism 0 0.0 273 Of Plasma Protein Metabolism 5 0.4 275 Of Mineral Metabolism 7 0.6 2770 Cystic Fibrosis 31 2.5 continued next page

26


Codes Defects Number N/10,000 2771-9 Other Metabolism 6 0.5 279 Of Immunity 6 0.5 280-9 Diseases of Blood 54 4.3 282 Hereditary Haemolytic Anaemia 51 4.1 281/3-5 Other Anaemias 1 0.1 286 Coagulation Defects 2 0.2 287-9 Other 0 0.0 315/8 Developmental Delay/Problems* 3 0.2 (also 783-786) * Very incomplete ascertainment of developmental delay.

27

2.6 Indications for Terminations of Pregnancy for a Birth Defect Before 20 Weeks Gestation, 1989—2000

Between 1989—2000 there were 2,683 terminations of pregnancy for birth defects before 20 weeks reported to the BDR. Of these cases, almost 50% of terminations were for a chromosomal anomaly and another 23% for Central Nervous System (CNS) Defects (mainly Anencephaly or Spina Bifida). For the period 19992000, 60% of terminations were for chromosomal anomalies and 17% for CNS Defects.

Table 2.6 Indications for Terminations of Pregnancy for a Birth Defect Before 20 Weeks Gestation by Body System, 1989—2000

Defect 19891993 % 19941998 % 19992000 %Chromosomal 335 44.5 655 48.4 344 59.5Central Nervous System 209 27.8 305 22.5 100 17.3 Cardiac System 20 2.7 27 2.0 16 2.8 Respiratory System 2 0.3 5 0.4 0 0.0 Digestive System 1 0.1 5 0.4 3 0.5 Genitourinary System 13 1.7 29 2.1 16 2.8 Musculoskeletal System 39 5.2 57 4.2 29 5.0 Multiple System 80 10.6 163 12.0 40 6.9 Other 46 6.1 85 6.3 19 3.3 Not otherwise specified 7 0.9 22 1.6 11 1.9 Total 752 100.0 1,353 100.0 578 100.0

Table 2.7 Specific Indications for Terminations of Pregnancy for a Birth Defect Before 20 Weeks Gestation, 1989—2000

Defect 19891993

n=752

19941998

n=1,353

19992000

n=578Chromosomal Down Syndrome (inc. tris/mosaic/trans) 136 300 181 Patau Syndrome (inc. tris/mosaic/trans) 25 45 27 Edward Syndrome (inc./mosaic/transloc.) 56 113 45 Conditions due to Other Autosomal Anomalies 58 81 41 Turner’s Syndrome 40 59 33 Klinefelter’s Syndrome 7 21 7 Conditions due to Other Sex Chromosome Anomalies 11 27 3 Conditions due to Other Chromosome Anomalies 2 9 6 Total 335 655 343Central Nervous System (CNS) Anencephaly 89 135 36 Spina Bifida with or without Hydrocephalus 60 90 44 Encephalocele 8 10 5 Mutiple Neural Tube Defects 18 20 2 Hydrocephalus 24 37 6 Other CNS Defects 10 13 7 Total 209 305 100

28

Table 2.7 Specific Indications for Terminations of Pregnancy for a Birth Defect Before 20 Weeks Gestation, 1989—2000 (cont)

Defect 19891993 19941998 19992000Cardiac System Hypoplastic Left Heart Syndrome 2 4 2 Multiple Cardiac 9 12 6 Other Cardiac Conditions (Single) 5 7 1 Cardiac System NOS 4 4 7 Total 20 27 16Respiratory System Cystic Lung 2 3 0 Other Respiratory 0 2 0 Total 2 5 0Digestive System Cleft Lip +/- palate 1 4 3 Tracheo-Oesohageal Fistula 0 1 0 Total 1 5 3Genito-Urinary System Potter's Syndrome 1 9 8 Cystic Kidney 6 6 3 Multiple Anomalies of the Urinary System 5 10 2 Other Anomalies of the Urinary System 1 4 3 Total 13 29 16Musculoskeletal System Chondrodystrophy 5 12 7 Skeletal Dysplasia (Osteodystrophy) 4 5 3 Diaphragmatic Hernia 4 4 2 Exomphalos 0 4 5 Gastroschisis 0 3 0 Other Musculoskeletal 7 12 5 Multiple Musculoskeletal 18 15 7 Musculoskeletal NOS 8 2 0 Total 39 57 29Neoplasms 0 2 2Thalassaemia 13 24 7 Haemophilia 1 1 1 Cystic Fibrosis 8 7 1 Cystic Hygroma 3 11 1 Phenylketonuria 2 0 0 Other Metabolic/Genetic Disorders 4 4 4 Huntington Disease 1 5 3 Werdnig-Hoffman Disease 1 3 0 Muscular Dystrophy 1 8 0 Hydrops Fetalis 5 11 0 Congenital Infections 2 1 0 Other 5 8 0 Total 46 85 19Multiple System Defects 80 163 40Congenital Anomalies NOS 7 22 11

29

3. Birth Defect Cases by Selected Infant Characteristics

Table 3.1 Birth Defect Cases by Number of Defects per Case 1999—2000

Number No. Cases % 1 3,760 74.1 2 721 14.2 3 264 5.2 4+ 331 6.5 Total 5,076 100.0 • 5,076 birth defect cases were notified to the BDR, comprising 7,876 individual birth defects

• 74.1% of cases had an isolated defect.

Table 3.2 Birth Defect Cases by Infant Sex, 1999—2000

Gender No. Cases % Total No. Births + TOPs

% N/10,000 95% Confidence Interval LL UL

Male 2,852 56.2 64,370 51.2 443.1 427.2 518.6 Female 2,052 40.4 61,278 48.7 334.9 320.6 412.7 Indeterminate 14 0.3 21 0.0 N/A N/A N/A Unknown 158 3.1 162 0.1 N/A N/A N/A Total 5,076 100.0 125,831 100.0 403.4 392.5 457.5 • Birth defects were more commonly reported in males than in females (ie 4.4% of all males

versus 3.3% of all females). This gives a relative risk of having a birth defect for males of 1.14 (95% CI 1.11-1.17, p<0.0001).

• There were 14 cases of indeterminate sex, as distinct from unknown. All births of indeterminate sex are considered to be birth defects.

Table 3.3 Birth Defect Cases by Birthweight (excluding TOPs) , 1999—2000

Weight No. Cases % Total No. Births


<1000 335 7.4 1,079 0.9 3,104.7 2,828.6 3,600.2 1000-2499 634 14.1 7,438 5.9 852.4 788.9 1,069.7 2500 + 3,519 78.2 116,720 93.2 301.5 291.7 358.0 Unknown 10 0.2 16 0.1 N/A N/A N/A Total 4,498 100.0 125,253 100.0 359.1 348.8 413.5 • Birth defects were recorded among 11.4% (969/8,517) of low birthweight infants (<2500

grams) compared with 3.0% (3,519/116,720) of infants with birthweights of 2500 grams or more.

30

Table 3.4 Birth Defect Cases by Gestational Age (excluding TOPs), 1999—2000

Gestation No. Cases % Total No. Births


20-27 317 7.0 1,008 0.8 3,144.8 2,858.2 3,656.0 28-31 167 3.7 962 0.8 1,736.0 1,496.6 2,310.4 32-36 520 11.6 7,653 6.1 679.5 623.1 895.8 37-41 3,439 76.5 113,815 90.9 302.2 292.2 359.4 > 41 51 1.1 1,798 1.4 283.6 206.9 739.3 Unknown 4 0.1 17 0.0 N/A N/A N/A Total 4,498 100.0 125,253 100.0 359.1 348.8 413.5 • 10.4% (1,004/9,623) of premature infants (< 37 weeks) had a birth defect compared to 3.0%

(3,444/115,613) among term and post-term infants (>= 37 weeks).

Table 3.5 Birth Defect Cases by Plurality, 1999—2000

Plurality No. Cases % Total No. Births + TOPS


Single 4,836 95.3 121,692 96.7 397.4 386.4 452.5 Twin 226 4.5 3,970 3.2 569.3 497.2 871.4 Triplet 10 0.2 164 0.1 609.8 243.5 2,092.9 Quad 3 0.1 4 0.0 7,500.0 3,256.5 12,400.0 Unknown 1 0.0 1 0.0 N/A N/A N/A Total 5,076 100.0 125,831 100.0 403.4 392.5 457.5 • 4.0% (4,836/121,692) of singleton births had a birth defect.

• 5.8% (239/4,138) of multiple births (twins, triplets, quads) had a birth defect.

• Relative risk of a birth defect for multiple versus singleton birth is 1.46 (95% CI 1.28-1.66,p <0.0001)

Table 3.6 Perinatal Mortality Associated with Birth Defect Cases, 1999—2000

Status No. Cases

% Total No. Births + TOPS


Liveborn surviving >28 days

4,092 80.6 123,951 99.0 330.1 320.2 384.9

Neonatal death 196 3.9 416 0.3 4,711.5 4,231.9 5,410.4 Stillborn 210 4.1 886 0.7 2,370.2 2,090.2 2,945.4 TOP < 20 weeks 578 11.4 578 0.4 N/A N/A N/A Total 5,076 100.0 125,831 100.0 403.4 392.5 457.5 1. Perinatal mortality is high among infants with birth defects.

• 11.4% of all pregnancies with a birth defect were terminated before 20 weeks gestation

• Of babies born at 20 weeks or more with a birth defect, 210 (4.7%) were stillborn and 196 (4.4%) were neonatal deaths. This corresponds to a perinatal mortality rate of 90.3/1,000 births with a defect.

31

• These mortality figures comprise all birth defect cases, including those where the cause of death may not be directly related to the birth defect.

• Relative risk of a perinatal death for a baby with a birth defect compared to a baby without a birth defect is 12.16 (95% CI 10.86,13.63,p < 0.0001).

2. Birth defects are a major contributor to perinatal mortality.

• Between 19992000 there were 886 stillbirths, 210 (23.7%) had a birth defect.

• Between 19992000 there were 416 neonatal deaths, 196 (47.1%) had a birth defect.

• 31.2% of all perinatal deaths were associated with one or more birth defects.

33

4. Birth Defect Cases by Selected Maternal Characteristics

Table 4.1 Birth Defect Cases by Maternal Age Group, 1999—2000

Age Group No. Cases % Total No. Cofinements +

TOPs


<20 191 3.8 4,045 3.3 472.2 406.8 537.6 20-24 614 12.4 15,671 12.7 391.8 361.4 422.2 25-29 1,509 30.4 38,496 31.1 392.0 372.6 411.4 30-34 1,511 30.4 42,250 34.1 357.6 339.9 375.3 35-39 868 17.5 19,730 15.9 439.9 411.3 468.6 40+ 246 5.0 3,519 2.8 699.1 614.8 783.3 Unknown 24 0.5 27 0.0 N/A N/A N/A Total 4,963 100.0 123,738 100.0 401.1 390.2 412.0 • The prevalence of birth defects is highest among mothers aged less than 20 (472/10,000) and

greater than 35 (440/10,000), with the prevalence greatest among women aged 40 years or more (699/10,000).

• Women aged 35 years and over comprise 22.5% of all mothers who have a pregnancy affected by a birth defect and have a relative risk of 1.21 compared to younger women (95%CI 1.15-1.28,p<0.0001).

• If all mothers with pregnancies affected by chromosomal abnormalities (Trisomy 21 , Trisomy 18 and Trisomy 13) are excluded, then the proportion of women aged 35 or more who have a pregnancy affected by a birth defect is 19.5%, giving a relative risk of having a child with a birth defect 1.04 compared to younger women (95% CI 0.98-1.11, p<0.0001).

Table 4.2 Birth Defect Cases by Maternal Country of Birth, 1999—2000

Country No. Cases % Total No. Confinements +

TOPs


Australia 3,661 73.8 93,981 76.0 389.6 377.2 401.9 Oceania/NZ 117 2.4 3,073 2.5 380.7 313.1 448.4 UK inc Eire 166 3.3 4,152 3.4 399.8 340.2 459.4 Europe 179 3.6 4,376 3.5 409.1 350.4 467.7 Middle East 149 3.0 2,922 2.4 509.9 430.2 589.7 Asia 414 8.3 11,851 9.6 349.3 316.3 382.4 Nth America 26 0.5 654 0.5 397.6 247.8 547.3 Sth America 26 0.5 710 0.6 366.2 228.0 504.4 Africa 74 1.5 1,784 1.4 414.8 322.3 507.3 Unknown 151 3.0 235 0.2 N/A N/A N/A Total 4,963 100.0 123,738 100.0 401.1 390.2 412.0 • Women from the Middle East are more likely to have babies with a birth defect than women

from any of the other country of birth groups (although only Australian born women have a statistically significant lower rate).

34

Table 4.3 Birth Defect Cases by Department of Human Services Region, 1999—2000

Region No. Cases % Total No. Confinements +

TOPS


Barwon 294 5.9 8,186 6.6 359.2 318.8 399.5 Grampians 197 4.0 5,720 4.6 344.4 297.1 391.7 Loddon Mallee 243 4.9 7,111 5.7 341.7 299.5 383.9 Hume 279 5.6 6,426 5.2 434.1 384.3 484.0 Gippsland 219 4.4 5,490 4.4 398.9 347.1 450.7 W Metro 703 14.2 17,236 13.9 407.9 378.3 437.4 N Metro 904 18.2 20,511 16.6 440.7 412.6 468.8 E Metro 814 16.4 22,489 18.2 362.0 337.5 386.4 S Metro 1,178 23.7 28,052 22.7 419.9 396.5 443.4 Other# 130 2.6 2,516 2.0 516.7 430.2 603.2 Unknown 2 0.0 1 0.0 N/A N/A N/A Total 4,963 100.0 123,738 100.0 401.1 390.2 412.0 * Refers to women who reside outside Victoria but who birth at a Victorian hospital. # Region is based on mothers’ postcode of residence at the time of birth. • Women from Rural Regions (grouped) have a statistically significant decreased likelihood of

having a baby born with a defect when compared to Metropolitan Regions (grouped) (RR 0.94, 95% CI 0.89-0.98,p=0.008). This may be due to differences in ascertainment between Rural and Metropolitan regions and should be considered in interpretation of these data.

Table 4.4 Birth Defect Cases by Aboriginality* (excluding TOPs), 1999—2000

Aboriginality No. Cases % Total No. Confinements

% N/10,000

95% Confidence Interval LL UL

Yes 24 0.5 821 0.7 292.3 177.1 407.6 No 4,357 99.4 122,332 99.3 356.2 345.8 366.5 Unknown 4 0.1 6 0.0 N/A Total 4,385 100.0 123,159 100.0 356.0 345.7 366.4 *Recent reports (8) have indicated the poor reporting of Aboriginality to the PDCU, leading to possible under-

ascertainment of birth defects

• The prevalence of birth defects in pregnancies of women reported as Koori on the Perinatal Morbidity Statistics (PMS) Form is less than those reported as non-Koori (RR 0.82, 95% CI 0.54-1.22, p=0.325). However this difference is not statistically significant, as in the previous report (2).

35

Table 4.5 Birth Defect Cases by Marital Status (excluding TOPs), 19992000

Marital Status No. Cases % Total No. Confinements


Single 560 12.8 14,127 11.5 396.4 364.2 428.6 Divorced 27 0.6 521 0.4 518.2 327.9 708.6 Widowed 1 0.0 51 0.0 196.1 0.0 576.6 Separated 32 0.7 835 0.7 383.2 253.0 513.4 Married 3,273 74.6 92,794 75.3 352.7 340.8 364.6 De facto 485 11.1 14,737 12.0 329.1 300.3 357.9 Unknown 7 0.2 94 0.1 N/A N/A N/A Total 4,385 100.0 123,159 100.0 356.0 345.7 366.4 • If marital status is divided into unpartnered (single, separated, divorced, widowed) versus

partnered (defacto, married), there is a statistically significant increased relative risk of 1.13 (95% CI 1.05-1.21, p<0.001) for unpartnered women.

Table 4.6 Birth Defect Cases by Parity (excluding TOPs), 1999—2000

Parity No. Cases

% Total No. Confinements


One (index preg.) 1,949 44.4 51,075 41.5 380.8 364.2 397.4 Two 1,410 32.2 42,617 34.6 330.9 313.9 347.8 Three 669 15.3 19,462 15.8 343.8 318.1 369.3 Four 222 5.1 6,525 5.3 340.2 296.2 384.2 Five 82 1.9 2,088 1.7 392.7 309.4 476.0 Six or more 53 1.2 1,392 1.1 380.8 280.2 481.3 Unknown 0 0.1 0 0.0 N/A N/A N/A Total 4,385 100.0 123,159 100.0 356.0 345.7 366.4 • Primiparous women are more likely to have babies with birth defects than multiparous

women (RR 1.07, 95% CI 1.04-1.11, p<0.0001).

37

5. Major Birth Defects

5.1 Anencephaly

Figure 5.1 Prevalence and Number of Cases by Year

0.0

2.0

4.06.0

8.0

10.0

12.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

10

20

30

40

50

60

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Termination< 20 w eeksStillbornLiveborn, neonatal deathSurvived > 28 days

Number 30 31 29 40 38 37 55 50 50 35 29 20 N/10,000 4.7 4.6 4.4 6.0 5.9 5.7 8.6 7.9 8.0 5.6 4.6 3.2

Anencephaly British Paediatric Association code 740.02

Total or partial absence of the cranial vault, the covering skin and the brain tissue.

• The number of babies with anencephaly reported to the BDR (including terminations) increased until 1995 and remained steady for the following two years. Since then (1997) there has been a significant decline in numbers. This decline may reflect greater nutritional intake of periconceptional folate and thus a reduction in incidence of neural tube defects. See page 44 for combined data on all neural tube defects

38

Table 5.1.1 Anencephaly, 19992000, by Selected Infant Characteristics All Births including TOPS (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval

No. % No. % No. % No. % LL UL Total (n= 638)* 399 105 85 49 6.3 5.6 7.2

Survived > 28 days 0 0.0 0 0.0 0 0.0 0 0.0 Neonatal death 90 22.6 8 7.6 9 10.6 3 6.1 Stillbirth 133 33.3 17 16.2 13 15.3 7 14.3 Termination < 20 wks 176 44.1 80 76.2 63 74.1 39 79.6 Sex Male 134 33.6 38 36.2 26 30.6 15 30.6 4.1 3.2 5.1

Female 211 52.9 32 30.5 29 34.1 10 20.4 3.9 3.1 4.9

Unknown/Indeterminate# 54 13.5 35 33.3 30 35.3 24 49.0

Plurality

Singleton 375 94.0 100 95.2 80 94.1 48 98.0 6.2 5.5 7.1

Twin 21 5.3 5 4.8 4 4.7 1 2.0 8.8 4.2 16.2

Triplet 1 0.3 0 0.0 1 1.2 0 0.0 20.6 0.5 114.9

Other 2 0.5 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • By 1989 the number of terminations of pregnancy exceeded the number of stillbirths and

neonatal deaths, due to the relative ease with which this birth defect is detected in utero by ultrasound. Before 1992 information about terminations was not readily available and the numbers presented for the earlier time period are almost certainly an underestimate of the true overall prevalence. In 19992000, 80% of fetuses with anencephaly were detected during pregnancy and there was a termination of pregnancy.

• The excess of female babies with anencephaly that was apparent in the early years of monitoring is now not seen because of the high rate of termination of fetuses of unknown sex.

• There are no significant associations of anencephaly with the maternal characteristics, age country of birth and region of residence.

39

Table 5.1.2 Anencephaly, 1999—2000, by Selected Maternal Characteristics

Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval

No. % No. % No. % No. % LL ULTotal (n=637)* 399 104 85 49 6.4 5.6 7.3Maternal Age <20 13 3.3 2 1.9 5 5.9 2 4.1 7.2 3.3 13.720-24 79 19.8 16 15.4 12 14.1 2 4.1 5.8 3.9 8.325-29 157 39.3 31 29.8 27 31.8 22 44.9 6.7 5.3 8.330-34 88 22.1 34 32.7 30 35.3 11 22.4 6.0 4.8 7.635-39 33 8.3 15 14.4 10 11.8 11 22.4 6.6 4.6 9.240+ 2 0.5 3 2.9 1 1.2 1 2.0 5.4 1.8 12.6Unknown# 27 6.8 3 2.9 0 0.0 0 0.0 N/A Country of Birth Australia 194 48.6 71 68.3 60 70.6 30 61.2 5.7 4.9 6.7Oceania inc NZ 6 1.5 2 1.9 0 0.0 1 2.0 3.4 0.7 10.0UK inc Eire 15 3.8 4 3.8 6 7.1 2 4.1 8.5 4.4 14.9Europe 19 4.8 5 4.8 4 4.7 3 6.1 8.3 4.3 14.6Middle East 3 0.8 7 6.7 0 0.0 0 0.0 7.7 3.1 15.9Asia 18 4.5 9 8.7 12 14.1 6 12.2 7.7 5.1 11.3Nth America 0 0.0 1 1.0 1 1.2 0 0.0 10.3 1.2 37.1Sth America 2 0.5 1 1.0 0 0.0 1 2.0 9.5 1.1 34.1Africa 5 1.3 0 0.0 0 0.0 1 2.0 2.1 0.1 11.5Unknown# 137 34.3 4 3.8 2 2.4 5 10.2 N/A Region Barwon S W 23 5.8 9 8.7 9 10.6 4 8.2 8.7 5.5 13.2Grampians 14 3.5 5 4.8 3 3.5 0 0.0 4.9 2.1 9.7Loddon Mallee 28 7.0 7 6.7 4 4.7 2 4.1 5.8 3.1 9.9Hume 23 5.8 3 2.9 7 8.2 0 0.0 5.2 2.5 9.6Gippsland 21 5.3 4 3.8 6 7.1 0 0.0 5.6 2.7 10.2Western Metro 54 13.5 20 19.2 14 16.5 8 16.3 8.4 6.0 11.4Northern Metro 68 17.0 18 17.3 10 11.8 12 24.5 6.3 4.5 8.6Eastern Metro 78 19.5 15 14.4 16 18.8 10 20.4 6.0 4.3 8.2Southern Metro 87 21.8 21 20.2 14 16.5 12 24.5 5.6 4.1 7.4Other 3 0.8 2 1.9 1 1.2 1 2.0 7.4 2.0 19.1Unknown 0 0.0 0 0.0 1 1.2 0 0.0 N/A *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks

Table 5.1.3 Patterns of Birth Defects, Anencephaly, 1999—2000

Type TOP < 20 Weeks

Stillbirth Neonatal Death

Surviving > 28 Days

Total % of Total

Isolated anomaly* 33 2 2 0 37 75.5Chromosomal 0 0 0 0 0 0.0 Other Same System (CNS) 2 1 0 0 3 6.1 Other Different Systems 4 4 1 0 9 18.4 Total 39 7 3 0 49 100.0* See p. 7 for the definition of an “isolated” anomaly.

40

5.2 Spina Bifida

Figure 5.2 Spina Bifida, Number of Cases by Year

3.0

5.0

7.0

9.0

11.0

13.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

10

20

30

40

50

60

70

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Surv ived > 28 days Liveborn, neonatal deathStillborn Termination< 20 w eeks

Number 55 59 49 49 51 60 64 51 60 32 50 43 N/10,000 8.5 8.8 7.5 7.4 7.9 9.2 10.0 8.1 9.6 5.1 7.9 6.8

Spina Bifida British Paediatric Association code 741.00 - 741.99

Non-closure of the spine resulting in herniation or exposure of the spinal cord and / or meninges. Hydrocephalus may or may not be present.

• This has always been reported more frequently than other neural tube defects. There has been a decline in prevalence from 8.3/10,000 between 19831994 to 7.9/10,000 between 19952000. This compares with a prevalence of anencephaly of 5.3/10,000 in the early years to 5.8/10,000 in 19952000. The difference in prevalence between these two neural tube defects may be due to ascertainment differences if information on early pregnancy terminations associated with anencephaly is missing. Other birth defect reports (from interstate and overseas) usually report similar prevalence figures for these two birth defects.

• The trend graph shows a non-significant decline in prevalence over the whole reporting period, but this decline has been significant since 1995 and is seen as a result of effective use of periconceptional folate (see page 44 for combined NTD data trend graph) .

• Approximately three quarters of cases of both spina bifida and anencephaly are found as isolated defects.

41

Table 5.2.1 Spina Bifida, 19992000, by Selected Infant Characteristics All Births including TOPS (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval


Survived > 28 days 236 36.5 27 23.5 20 21.7 20 21.5 1.8 1.4 2.3

Neonatal death 140 21.6 11 9.6 10 10.9 7 7.5 Stillbirth 123 19.0 21 18.3 15 16.3 15 16.1 Termination < 20 wks 148 22.9 56 48.7 47 51.1 51 54.8 Sex Male 285 44.0 46 40.0 42 45.7 47 50.5 6.9 5.9 8.3

Female 314 48.5 54 47.0 39 42.4 33 35.5 6.9 5.8 8.2


Plurality

Singleton 627 96.9 111 96.5 92 100.0 89 95.7 8.0 7.1 9.0

Twin 19 2.9 4 3.5 0 0.0 4 4.3 7.0 3.1 13.8

Triplet 1 0.2 0 0.0 0 0.0 0 0.0 0.0

Other 0 0.0 0 0.0 0 0.0 0 0.0 N/A *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • Since 1993 the number of terminations has exceeded the number of births.

• The proportion of babies surviving beyond 28 days has decreased from 36% in 19831994 to 23% in 19951998 to 21% since then, meaning that, on average, 10 babies a year are surviving with spina bifida.

• There was no difference in the proportion of male and females with spina bifida and this condition was not seen more often in twins.

• There is an inverse linear trend with maternal age with women in younger age groups at greater risk than older women, and women aged 20-24 years having a particularly high risk compared with older women.

• This neural tube defect is not as common in births to Asian-born women and the prevalence is significantly different from that of Australian-born women.

• There are no significant regional variations.

42

Table 5.2.2 Spina Bifida, 1999—2000, by Selected Maternal Characteristics


(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Table 5.2.3 Patterns of Birth Defects, Spina Bifida, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


43

5.3 Encephalocele


0.0

1.0

2.0

3.0

4.0

5.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Termination< 20 w eeksStillbornLiveborn, neonatal deathSurv ived > 28 days

Number 8 12 7 19 9 21 9 11 15 6 12 13 N/10,000 1.2 1.8 1.1 2.9 1.4 3.2 1.4 1.7 2.4 1.0 1.9 2.1

Encephalocele British Paediatric Association code 742.00 - 742.09

Cystic expansion (herniation) of meninges and brain tissue outside the cranium, covered by normal or atrophic skin.

• This is the least common of the neural tube defects with only 25 cases reported from 19992000 and an overall prevalence of 1.7/10,000. The decline in overall prevalence that was observed for anencephaly and spina bifida in recent years was not observed for encephalocele.

• Many babies are stillborn or die in the newborn period, this birth defect often being associated with others (in 48% of cases).

• There is a non-significant excess of females and affected twin pregnancies are more common, however, the numbers are small and these are not significant differences.

• There is no association with maternal age.

44

Table 5.3.1 Encephalocele, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval


Survived > 28 days 55 37.4 10 50.0 6 28.6 7 28.0 0.6 0.4 0.9


Female 77 52.4 10 50.0 14 66.7 12 48.0 2.0 1.4 2.7

Unknown/Indeterminate# 8 5.4 1 5.0 2 9.5 4 16.0 N/A

Plurality

Singleton 140 95.2 18 90.0 21 100.0 24 96.0 1.7 1.3 2.2

Twin 7 4.8 2 10.0 0 0.0 1 4.0 2.6 0.5 7.7

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks

• There is a borderline significant two-fold increased risk of encephalocele in the Asian-born women, compared with Australian-born women. This compares with spina bifida which is less likely to occur in Asian-born women.

• The following graph is a summary of the prevalence of all neural tube defects reported to the Birth Defects Register since 1995 and shows that overall there has been a 40% decrease in prevalence since then, from 20/10,000 to 12.1/10,000 in 2000. (χ2 for linear trend = 18.7, p<0.0001

All neural tube defects 1995 – 2000

5

10

15

20

25

1995 1996 1997 1998 1999 2000

n/10

,000

45

Table 5.3.2 Encephalocele, 1999—2000, by Selected Maternal Characteristics


(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Table 5.3.3 Patterns of Birth Defects, Encephalocele, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total

Isolated anomaly* 5 2 0 6 13 52.0Chromosomal 0 0 0 0 0 0.0 Other Same System (CNS) 2 1 0 1 4 16.0 Other Different Systems 5 2 1 0 8 32.0 Total 12 5 1 7 25 100.0* *See p.7 for the definition of an “isolated” anomaly.

46

5.4 Microcephalus


0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Termination< 20 w eeksStillbornLiv eborn, neonatal deathSurv iv ed > 28 day s

Number 18 23 19 13 18 18 28 14 15 22 16 12 N/10,000 2.8 3.4 2.9 2.0 2.8 2.8 4.4 2.2 2.4 3.5 2.5 1.9

Microcephalus British Paediatric Association code 742.19

Reduction in the size of the brain, with head circumference less than three standard deviations below the mean measurement for the same gestation or age. There are multiple known and unknown causes of microcephaly and it therefore cannot be considered as a single condition.

• There has been a non-significant decline in the overall prevalence of microcephaly since 1983

(χ2 for linear trend = 5.02, p =0.02). In 1995 there was a large increase, but otherwise the numbers shown annual fluctuations that are sometimes observed. We do not know whether there may have existed some contributing unidentified causal agent that year or whether this was just a chance fluctuation.

• The original decline is thought to be the result of reporting inconsistencies - in the earlier years absolute microcephaly may have been reported to the BDR i.e. head circumference below the third standard deviation from the mean, no matter whether the baby was also of low birth weight (due to IUGR or prematurity). Such practice has changed, with relative microcephaly being the usual criterion for reporting in more recent years.

47

Table 5.4.1 Microcephaly, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval No. % No. % No. % No. % LL UL Total (n= 348)* 241 42 37 28 2.8 2.3 3.4

Survived > 28 days 160 66.4 35 83.3 24 64.9 15 53.6 2.0 1.6 2.5


Female 129 53.5 21 50.0 20 54.1 16 57.1 3.1 2.4 4.1


Plurality

Singleton 226 93.8 40 95.2 35 94.6 26 92.9 2.5 2.1 3.1

Twin 15 6.2 2 4.8 2 5.4 2 7.1 5.3 1.9 11.5

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0


• There are almost no terminations of pregnancy before 20 weeks reported for this condition, which is interesting as perinatal deaths occur in 43% of cases and there is a high frequency of this condition with other defects (86%).

• There are no significant differences in sex, plurality, maternal age or region of residence.

• There is an increased risk for women of Middle Eastern background, compared with Australian-born women.

48

Table 5.4.2 Microcephalus, 1999—2000, by Selected Maternal Characteristics


(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Table 5.4.3 Patterns of Birth Defects, Microcephalus, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total

Isolated anomaly* 0 0 0 4 4 14.3Chromosomal 1 1 3 2 7 25.0 Other Same System (CNS) 0 0 1 2 3 10.7 Other Different Systems 0 4 3 7 14 50.0 Total 1 5 7 15 28 100.0*See p.7 for the definition of an “isolated” anomaly.

49

5.5 Hydrocephalus


0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

10

20

30

40

50

60

70

80

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Term ination< 20 weeksStillbornLiveborn, neonatal deathSurvived > 28 days

Number 40 50 51 50 55 61 58 48 64 58 64 67 N/10,000 6.2 7.5 7.8 7.5 8.5 9.4 9.1 7.6 10.2 9.3 10.2 10.7

Hydrocephalus British Paediatric Association code 742.30 - 742.39

Dilatation of the ventricular system, not due to primary atrophy of brain and not necessarily associated with enlargement of the skull. These cases exclude hydrocephalus associated with spina bifida.

• There has been a significant increase in overall prevalence (χ2 linear trend = 48.12, p<0.0001) with an increase from less than 40 births per year to over 60 per year in 19992000

• Some increase reflects better ascertainment with new technologies enabling recognition of dilated ventricles otherwise missed.

- Mild cases of hydrocephaly are diagnosed by CAT scanning which is used more frequently than in the early and mid 1980s. Then it was used only when there was a strong indication to do so.

- Affected fetuses are being diagnosed prenatally by routine ultrasound leading to an increased number of pregnancy terminations. There has been no increase in prenatal detection and pregnancy termination in recent years.

50

Table 5.5.1 Hydrocephalus, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 196 39.5 39 36.8 49 40.2 62 47.3 4.0 3.4 4.7


Female 207 41.7 49 46.2 52 42.6 51 38.9 8.3 7.1 9.8


Plurality

Singleton 461 92.9 100 94.3 115 94.3 121 92.4 9.2 8.2 10.2

Twin 32 6.5 6 5.7 7 5.7 10 7.6 20.2 12.8 30.3

Triplet 3 0.6 0 0.0 0 0.0 0 0.0 0.0


• There is a stillbirth rate of 23% and another 19% of pregnancies are terminated before 20 weeks. There are about 30 babies surviving the neonatal period each year.

• There is a non-significant excess of males with hydrocephalus.

• This defect is significantly more prevalent in twin pregnancies compared with singletons.

• There is a non-significant U-shaped association with maternal age: an increased risk for teenage women and those over 40 years of age, compared to women of all other ages.

• There is no significant association with maternal country of birth, but Middle Eastern women are at highest risk.

• This occurs as an isolated anomaly in 43% of cases.

51

Table 5.5.2 Hydrocephalus, 1999—2000, by Selected Maternal Characteristics


(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Table 5.5.3 Patterns of Birth Defects, Microcephalus, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


52

5.6 Transposition of Great Vessels


0.01.02.03.04.05.06.07.08.09.0

10.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

40

45

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000Survived > 28 days Liveborn, neonatal death Stillborn Termination< 20 w eeks

Number 38 28 32 35 35 44 39 37 30 28 36 32N/10,000 5.9 4.2 4.9 5.3 5.4 6.8 6.1 5.9 4.8 4.5 5.7 5.1

Transposition of Great Vessels British Paediatric Association code 745.10 - 745.19

Maldivision of the arterial truncus causes the aorta to emerge from the right ventricle and the pulmonary truncus from the left ventricle.

• The decline in birth prevalence from 19941998 did not continue in 19992000 and an increase in surviving babies is observed .

• Almost 70% survive the neonatal period - this is not a lethal malformation if a successful operation is performed.

53

Table 5.6.1 Transposition of Great Vessels, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 305 82.0 55 72.4 40 69.0 47 69.1 3.8 3.2 4.5


Female 126 33.9 32 42.1 24 41.4 20 29.4 4.1 3.3 5.2


Plurality

Singleton 351 94.4 74 97.4 57 98.3 67 98.5 5.4 4.7 6.2

Twin 19 5.1 2 2.6 0 0.0 1 1.5 2.6 0.5 7.7

Triplet 2 0.5 0 0.0 1 1.7 0 0.0 20.6 0.50 114.9


• There is a significant excess of males with this condition.

• There are no significant associations with mother’s age, or region of residence.

• This condition is twice as prevalent in babies born to women from UK/Eire compared with Australian- and Asian-born women, but this significant difference has not been observed in previous years.

• This is often associated with another cardiac defect (62%).

54

Table 5.6.2 Transposition of Great Vessels, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence Interval

No. % No. % No. % No. % LL UL

Total (n=573)* 371 76 58 68 5.4 4.7 6.2

Maternal Age

<20 13 3.5 3 3.9 3 5.2 1 1.5 5.6 2.2 11.5

20-24 53 14.3 17 22.4 13 22.4 7 10.3 7.2 5.1 9.9

25-29 152 41.0 21 27.6 20 34.5 27 39.7 5.7 4.4 7.2

30-34 104 28.0 22 28.9 11 19.0 20 29.4 4.3 3.2 5.6

35-39 41 11.1 11 14.5 10 17.2 9 13.2 5.5 3.7 7.9

40+ 7 1.9 1 1.3 1 1.7 2 2.9 4.3 1.2 11.1

Unknown# 1 0.3 1 1.3 0 0.0 2 2.9 N/A

Country of Birth

Australia 274 73.9 56 73.7 41 70.7 45 66.2 5.1 4.3 6.0

Oceania inc NZ 8 2.2 1 1.3 1 1.7 3 4.4 5.7 1.8 13.3

UK inc Eire 19 5.1 6 7.9 3 5.2 7 10.3 11.3 6.5 18.3

Europe 28 7.5 6 7.9 2 3.4 1 1.5 6.2 2.9 11.9

Middle East 11 3.0 2 2.6 1 1.7 2 2.9 5.5 1.8 12.9

Asia 20 5.4 3 3.9 6 10.3 3 4.4 3.4 1.8 6.0

Nth America 2 0.5 0 0.0 1 1.7 0 0.0 5.1 0.1 28.6

Sth America 3 0.8 0 0.0 1 1.7 0 0.0 4.7 0.1 26.3

Africa 1 0.3 1 1.3 2 3.4 3 4.4 12.4 4.6 27.1

Unknown# 5 1.3 1 1.3 0 0.0 4 5.9 N/A

Region

Barwon S W 33 8.9 4 5.3 1 1.7 2 2.9 2.8 1.1 5.7

Grampians 13 3.5 4 5.3 4 6.9 1 1.5 5.5 2.5 10.5

Loddon Mallee 23 6.2 6 7.9 4 6.9 6 8.8 7.2 4.1 11.6

Hume 17 4.6 2 2.6 1 1.7 2 2.9 2.6 0.8 6.1

Gippsland 25 6.7 1 1.3 4 6.9 3 4.4 4.4 1.9 8.8

Western Metro 45 12.1 10 13.2 8 13.8 10 14.7 5.6 3.7 8.1

Northern Metro 57 15.4 15 19.7 12 20.7 7 10.3 5.3 3.7 7.5

Eastern Metro 66 17.8 16 21.1 8 13.8 14 20.6 5.6 4.0 7.7

Southern Metro 90 24.3 16 21.1 15 25.9 20 29.4 6.1 4.6 8.0

Other 1 0.3 2 2.6 1 1.7 2 2.9 9.3 3.0 21.7

Unknown 1 0.3 0 0.0 0 0.0 1 1.5 N/A

*See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks

Table 5.6.3 Patterns of Birth Defects, Transposition of Great Vessels, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


55

5.7 Tetralogy of Fallot


0.01.02.03.04.05.06.07.0

83-85

86-88

89-91

1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35


Number 14 27 32 31 22 31 26 25 25 23 27 33 N/10,000 2.2 4.0 4.9 4.7 3.4 4.8 4.1 4.0 4.0 3.7 4.3 5.3

Tetralogy of Fallot British Paediatric Association code 745.20

An anomaly of the heart consisting of pulmonary stenosis, interventricular septal defect, dextraposed aorta that receives blood from both ventricles and hypertrophy of the right ventricle.

• The overall birth prevalence before 1990 was generally lower than in later years, but this may

reflect the method of reporting only. This condition used to be reported as VSD plus pulmonary stenosis or atresia and was not necessarily called Tetralogy of Fallot. Reporting changed in about 1990 at the Royal Children’s Hospital so that nomenclature of cases included Tetralogy of Fallot. There is lower overall prevalence of Tetralogy of Fallot (4.2/10,000) compared with Transposition of the Great Vessels (5.3/10,000).

56

Table 5.7.1 Tetralogy of Fallot, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 234 90.0 40 78.4 41 85.4 45 75.0 3.4 2.8 4.0


Female 103 39.6 25 49.0 17 35.4 19 31.7 3.3 2.6 4.3


Plurality

Singleton 250 96.2 48 94.1 46 95.8 54 90.0 4.0 3.4 4.8

Twin 10 3.8 3 5.9 2 4.2 6 10.0 9.7 4.8 17.3

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0


• There has been a slight decline in the proportion of cases that survive the neonatal period: 90% in 198394, 82% in 199598 and 75% in 19992000. The increase in neonatal deaths may be because of the presence of another defect, this occurring in 63% of cases.

• There is a non- significant excess of males with this condition.

• There is a significant increased risk for women 35-39 years compared with women 30-34 years.

• There is no significant maternal country of birth or regional associations.

57

Table 5.7.2 Tetralogy of Fallot, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=418) 260 51 48 59 4.2 3.6 5.0

Maternal Age

<20 9 3.5 3 5.9 2 4.2 2 3.4 5.6 2.2 11.5

20-24 50 19.2 11 21.6 6 12.5 2 3.4 3.7 2.2 5.8

25-29 89 34.2 14 27.5 14 29.2 19 32.2 3.9 2.8 5.2

30-34 74 28.5 14 27.5 17 35.4 12 20.3 3.5 2.5 4.7

35-39 33 12.7 8 15.7 8 16.7 22 37.3 7.0 4.9 9.6

40+ 4 1.5 1 2.0 0 0.0 2 3.4 3.3 0.7 9.5

Unknown# 1 0.4 0 0.0 1 2.1 0 0.0 N/A

Country of Birth

Australia 190 73.1 37 72.5 29 60.4 48 81.4 4.1 3.4 4.9

Oceania inc NZ 2 0.8 1 2.0 0 0.0 0 0.0 1.1 0.0 6.3

UK inc Eire 17 6.5 0 0.0 2 4.2 0 0.0 1.4 0.2 5.1

Europe 12 4.6 2 3.9 4 8.3 3 5.1 6.2 2.9 11.9

Middle East 3 1.2 3 5.9 0 0.0 1 1.7 4.4 1.2 11.3

Asia 29 11.2 5 9.8 10 20.8 6 10.2 6.0 3.7 9.2

Nth America 0 0.0 2 3.9 0 0.0 1 1.7 15.4 3.2 45.0

Sth America 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Africa 2 0.8 1 2.0 2 4.2 0 0.0 6.2 1.3 18.1

Unknown# 5 1.9 0 0.0 1 2.1 0 0.0 N/A

Region

Barwon S W 15 5.8 7 13.7 3 6.3 5 8.5 6.0 3.3 9.8

Grampians 9 3.5 1 2.0 1 2.1 2 3.4 2.5 0.7 6.3

Loddon Mallee 23 8.8 1 2.0 0 0.0 2 3.4 1.3 0.3 3.9

Hume 12 4.6 3 5.9 3 6.3 1 1.7 3.7 1.5 7.6

Gippsland 13 5.0 0 0.0 1 2.1 3 5.1 2.2 0.6 5.7

Western Metro 37 14.2 10 19.6 7 14.6 10 16.9 5.4 3.6 7.9

Northern Metro 50 19.2 11 21.6 11 22.9 10 16.9 5.0 3.4 7.1

Eastern Metro 50 19.2 7 13.7 10 20.8 13 22.0 4.4 3.0 6.3

Southern Metro 50 19.2 10 19.6 12 25.0 12 20.3 4.0 2.8 5.6

Other 1 0.4 1 2.0 0 0.0 1 1.7 3.7 0.5 13.4

Unknown 0 0.0 0 0.0 0 0.0 0 0.0 N/A *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks

Table 5.7.3 Patterns of Birth Defects, Tetralogy of Fallot, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


58

5.8 Ventricular Septal Defect


15.0

20.0

25.0

30.0

35.0

40.0

83-85

86-88

89-91

1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

50

100

150

200

250

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Survived > 28 days Liveborn, neonatal death Stillborn Termination< 20 w eeks

Number 186 219 205 205 191 234 199 180 194 174 192 214 N/10,000 28.9 32.7 31.4 30.8 29.4 35.9 31.1 28.5 31.0 27.9 30.5 29.9

Ventricular Septal Defect British Paediatric Association code 745.40 - 745.49

A defect in the septum between the left and right ventricles of the heart, which permits blood to be shunted between them.

• This is one of the most common defects reported and is seen with other cardiac defects in

27% of cases and as an isolated abnormality in 43% of cases.

• There was an increased overall prevalence recorded up to 1994 and fluctuating numbers have been evident since then with a prevalence of 30/10,000 in the last two years. However there is a significant increased prevalence for the entire reporting period (Χ2 for linear trend=33.1, p<0.0001).

• This defect is not often associated with death in the perinatal period.

• There are no significant sex differences in prevalence, but there is a significant two-fold increased prevalence in twins.

59

Table 5.8.1 Ventricular Septal Defect, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval No. % No. % No. % No. % LL UL Total (n= 3,214)* 2,061 379 368 406 30.5 28.7 32.3

Survived > 28 days 1,767 85.7 310 81.8 302 82.1 342 84.2 25.0 23.4 26.6

Neonatal death 134 6.5 21 5.5 24 6.5 22 5.4

Stillbirth 110 5.3 24 6.3 30 8.2 24 5.9

Termination < 20 wks 50 2.4 24 6.3 12 3.3 18 4.4

Sex Male 1,009 49.0 188 49.6 188 51.1 200 49.3 29.7 27.2 32.1

Female 1,037 50.3 184 48.5 179 48.6 203 50.0 30.9 28.4 33.4


Plurality

Singleton 1,972 95.7 355 93.7 342 92.9 374 92.1 29.3 27.5 31.0

Twin 87 4.2 22 5.8 20 5.4 31 7.6 64.1 50.6 81.1

Triplet 2 0.1 2 0.5 4 1.1 1 0.2 144.3 57.9 297.3

Other 0 0.0 0 0.0 2 0.5 0 0.0 N/A *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks

• There is a significantly higher frequency of the defect in babies born to women 40 years and over, compared with younger women. This is probably related to the association with Down syndrome and other chromosomal disorders in 14% of cases.

• There are no significant associations with mother’s country of birth

• There is significantly increased prevalence in Northern Metropolitan Region compared with several other regions (Loddon Mallee and Eastern Metropolitan), but this has not been noted in previous years.

60

Table 5.8.2 Ventricular Septal Defect, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=3,203)* 2,055 379 366 403 30.9 29.1 32.6

Maternal Age

<20 82 4.0 8 2.1 12 3.3 12 3.0 25.6 17.5 36.2

20-24 342 16.6 58 15.3 59 16.1 59 14.6 34.2 29.4 39.8

25-29 744 36.2 120 31.7 112 30.6 117 29.0 29.0 26.1 32.3

30-34 604 29.4 127 33.5 108 29.5 126 31.3 29.1 26.2 32.3

35-39 232 11.3 52 13.7 59 16.1 70 17.4 33.3 28.7 38.7

40+ 47 2.3 11 2.9 16 4.4 16 4.0 46.6 33.7 62.9

Unknown# 4 0.2 3 0.8 0 0.0 3 0.7 N/A

Country of Birth

Australia 1,511 73.5 257 67.8 263 71.9 309 76.7 29.5 27.5 31.5

Oceania inc NZ 39 1.9 9 2.4 9 2.5 12 3.0 34.1 23.0 48.8

UK inc Eire 113 5.5 20 5.3 15 4.1 17 4.2 36.8 27.7 48.6

Europe 118 5.7 21 5.5 9 2.5 12 3.0 29.1 21.0 39.4

Middle East 59 2.9 13 3.4 10 2.7 12 3.0 38.7 26.9 53.7

Asia 133 6.5 44 11.6 46 12.6 27 6.7 33.5 27.9 40.3

Nth America 12 0.6 1 0.3 2 0.5 2 0.5 25.7 8.3 59.8

Sth America 10 0.5 3 0.8 2 0.5 1 0.2 28.4 10.4 61.8

Africa 18 0.9 7 1.8 5 1.4 7 1.7 39.3 23.7 61.4

Unknown# 42 2.0 4 1.1 5 1.4 4 1.0 N/A

Region

Barwon S W 140 6.8 24 6.3 24 6.6 28 6.9 30.2 23.9 38.0

Grampians 97 4.7 14 3.7 21 5.7 15 3.7 30.7 22.8 40.6

Loddon Mallee 145 7.1 19 5.0 13 3.6 24 6.0 25.0 19.1 32.8

Hume 106 5.2 19 5.0 21 5.7 21 5.2 32.0 24.7 41.4

Gippsland 106 5.2 18 4.7 21 5.7 23 5.7 34.5 26.6 44.5

Western Metro 273 13.3 52 13.7 38 10.4 59 14.6 29.8 25.3 35.1

Northern Metro 336 16.4 85 22.4 73 19.9 85 21.1 38.2 33.6 43.4

Eastern Metro 413 20.1 63 16.6 58 15.8 55 13.6 25.9 22.3 30.1

Southern Metro 424 20.6 80 21.1 88 24.0 84 20.8 29.9 26.4 33.9

Other 13 0.6 5 1.3 9 2.5 8 2.0 40.9 25.7 61.8


Table 5.8.3 Patterns of Birth Defects, Ventricular Septal Defect, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


61

5.9 Hypoplastic Left Heart Syndrome


0.0

1.0

2.0

3.0

4.0

5.0

6.0

83-85

86-88

89-91

1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 16 15 17 21 15 15 12 17 22 13 23 20 N/10,000 2.5 4.0 2.6 3.2 2.3 2.3 1.9 2.7 3.5 2.1 3.7 3.2

Hypoplastic Left Heart Syndrome British Paediatric Association code 746.79

Severely underdeveloped left side of the heart as a result of aortic valve atresia, mitral valve atresia, or a combination of both.

• There has been no significant change in overall prevalence with numbers fluctuating each

year.

• This has a lower prevalence than the other major cardiac malformations (2.8/10,000), but is considerably more likely to be lethal, with 56% dying in the newborn period. Neonatal death rates were higher in 19831994 than in 19992000, but the proportion surviving beyond 28 days has not increased substantially because stillbirths and terminations have increased.

• There is no significant difference in the prevalence of this defect in male and female babies or in twins.

• There is no significant association with maternal age, country of birth or region of residence.

• This defect is often associated with other defects with only 26% reported as isolated cases.

62

Table 5.9.1 Hypoplastic Left Heart Syndrome, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 41 20.2 9 31.0 9 25.7 12 27.9 0.8 0.5 1.2

Neonatal death 130 64.0 10 34.5 13 37.1 10 23.3

Stillbirth 21 10.3 6 20.7 4 11.4 14 32.6

Termination < 20 wks 11 5.4 4 13.8 9 25.7 7 16.3

Sex Male 99 48.8 15 51.7 17 48.6 17 39.5 2.5 1.9 3.3

Female 99 48.8 13 44.8 17 48.6 24 55.8 2.9 2.2 3.9


Plurality

Singleton 200 98.5 29 100.0 35 100.0 41 95.3 2.9 2.4 3.5

Twin 3 1.5 0 0.0 0 0.0 2 4.7 1.8 0.2 6.3

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0


63

Table 5.9.2 Hypoplastic Left Heart Syndrome, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=310)* 203 29 35 43 2.9 2.4 3.5

Maternal Age

<20 10 4.9 0 0.0 1 2.9 3 7.0 3.2 0.9 8.2

20-24 37 18.2 4 13.8 11 31.4 8 18.6 4.5 2.8 6.7

25-29 83 40.9 12 41.4 5 14.3 15 34.9 2.7 1.8 3.8

30-34 53 26.1 5 17.2 8 22.9 12 27.9 2.0 1.3 3.0

35-39 15 7.4 7 24.1 8 22.9 5 11.6 2.4 1.4 3.7

40+ 4 2.0 1 3.4 2 5.7 0 0.0 3.3 0.7 9.5

Unknown# 1 0.5 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 157 77.3 25 86.2 27 77.1 32 74.4 3.0 2.4 3.7

Oceania inc NZ 6 3.0 1 3.4 0 0.0 4 9.3 5.7 1.8 13.3

UK inc Eire 6 3.0 1 3.4 1 2.9 0 0.0 1.4 0.2 5.1

Europe 7 3.4 1 3.4 1 2.9 1 2.3 2.1 0.4 6.1

Middle East 9 4.4 0 3.4 4 11.4 2 4.7 7.7 3.1 15.9

Asia 9 4.4 0 0.0 1 2.9 2 4.7 0.9 0.2 2.5

Nth America 1 0.5 1 3.4 0 0.0 0 0.0 5.1 0.1 28.6

Sth America 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Africa 1 0.5 0 0.0 1 2.9 0 0.0 2.1 0.1 11.5

Unknown# 7 3.4 0 0.0 0 0.0 2 4.7 N/A

Region

Barwon S W 14 6.9 3 10.3 1 2.9 2 4.7 2.4 0.9 5.2

Grampians 10 4.9 2 6.9 2 5.7 3 7.0 4.3 1.7 8.9

Loddon Mallee 9 4.4 2 6.9 3 8.6 2 4.7 3.1 1.3 6.4

Hume 18 8.9 1 3.4 5 14.3 0 0.0 3.1 1.2 6.9

Gippsland 8 3.9 2 6.9 1 2.9 1 2.3 2.2 0.6 5.7

Western Metro 25 12.3 8 27.6 6 17.1 11 25.6 5.0 3.2 7.4

Northern Metro 30 14.8 3 10.3 8 22.9 7 16.3 2.8 1.7 4.5

Eastern Metro 38 18.7 3 10.3 5 14.3 5 11.6 1.9 1.0 3.3

Southern Metro 50 24.6 5 17.2 3 8.6 10 23.3 2.1 1.3 3.4

Other 1 0.5 0 0.0 1 2.9 2 4.7 5.6 1.1 16.3

Unknown 0 0.0 0 0.0 0 0.0 0 0.0 0.0 N/A *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks

Table 5.9.3 Patterns of Birth Defects, Hypoplastic Left Heart Syndrome, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


64

5.10 Coarctation of Aorta


0.01.02.03.04.05.06.07.08.0

83-85

86-88

89-91

1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

40

45

50

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 40 49 24 37 33 25 34 26 19 26 19 22 N/10,000 6.2 7.3 3.7 5.6 5.1 3.8 5.3 4.1 3.0 4.2 3.0 3.5

Coarctation of Aorta British Paediatric Association code 747.10 - 747.19

Narrowing of the aorta, either distal or proximal to the ductus arteriosus.

• This cardiac malformation is the only sentinel cardiac defect that has declined significantly in

prevalence (χ2 for linear trend = 29.2, p<0.0001).

• It is often associated with other cardiac defects (44%).

• There is little association with neonatal death, 80% surviving this period.

• There is a non-significant excess in male babies and no increased prevalence in twins.

• There is no significant association with maternal age, country of birth or region of residence.

65

Table 3.10.1 Coarctation of Aorta, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 380 84.8 55 91.7 36 80.0 33 80.5 3.3 2.8 4.0

Neonatal death 52 11.6 4 6.7 7 15.6 3 7.3

Stillbirth 11 2.5 1 1.7 1 2.2 3 7.3

Termination < 20 wks 5 1.1 0 0.0 1 2.2 2 4.9

Sex Male 263 58.7 32 53.3 25 55.6 22 53.7 4.1 3.2 5.1

Female 181 40.4 28 46.7 20 44.4 18 43.9 3.6 2.8 4.6


Plurality

Singleton 429 95.8 59 98.3 44 97.8 39 95.1 3.9 3.3 4.6

Twin 18 4.0 1 1.7 1 2.2 2 4.9 3.5 1.0 9.0

Triplet 1 0.2 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0


66

Table 5.10.2 Coarctation of Aorta, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=593)* 447 60 45 41 4.6 3.9 5.4

Maternal Age

<20 17 3.8 4 6.7 2 4.4 1 2.4 5.6 2.2 11.5

20-24 77 17.2 12 20.0 12 26.7 3 7.3 5.2 3.5 7.7

25-29 187 41.8 20 33.3 11 24.4 12 29.3 3.6 2.6 4.8

30-34 128 28.6 14 23.3 12 26.7 16 39.0 3.4 2.4 4.6

35-39 33 7.4 10 16.7 6 13.3 6 14.6 4.1 2.5 6.1

40+ 4 0.9 0 0.0 1 2.2 3 7.3 4.3 1.2 11.1

Unknown# 1 0.2 0 0.0 1 2.2 0 0.0 N/A

Country of Birth

Australia 354 79.2 49 81.7 30 66.7 28 68.3 3.8 3.1 4.6

Oceania inc NZ 16 3.6 0 0.0 1 2.2 2 4.9 3.4 0.7 10.0

UK inc Eire 23 5.1 1 1.7 0 0.0 3 7.3 2.8 0.8 7.2

Europe 22 4.9 3 5.0 3 6.7 0 0.0 4.2 1.5 9.1

Middle East 7 1.6 2 3.3 2 4.4 2 4.9 6.6 2.4 14.4

Asia 16 3.6 4 6.7 4 8.9 4 9.8 3.4 1.8 6.0

Nth America 0 0.0 0 0.0 0 0.0 0 0.0 0.0 N/A N/A

Sth America 0 0.0 0 0.0 0 0.0 0 0.0 0.0 N/A N/A

Africa 6 1.3 1 1.7 3 6.7 1 2.4 10.4 3.4 24.1

Unknown# 3 0.7 0 0.0 2 4.4 1 2.4 N/A

Region

Barwon S W 32 7.2 4 6.7 4 8.9 4 9.8 4.8 2.5 8.3

Grampians 22 4.9 4 6.7 3 6.7 2 4.9 5.5 2.5 10.5

Loddon Mallee 44 9.8 3 5.0 2 4.4 4 9.8 4.0 1.8 7.6

Hume 29 6.5 2 3.3 6 13.3 2 4.9 5.2 2.5 9.6

Gippsland 20 4.5 3 5.0 0 0.0 1 2.4 2.2 0.6 5.7

Western Metro 56 12.5 8 13.3 9 20.0 9 22.0 5.2 3.4 7.6

Northern Metro 55 12.3 13 21.7 8 17.8 5 12.2 4.1 2.7 6.0

Eastern Metro 92 20.6 11 18.3 5 11.1 4 9.8 2.9 1.8 4.5

Southern Metro 92 20.6 12 20.0 5 11.1 8 19.5 3.0 1.9 4.4

Other 4 0.9 0 0.0 2 4.4 2 4.9 7.4 2.0 19.1


Table 5.10.3 Patterns of Birth Defects, Coarctation of Aorta, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


67

5.11 Cleft Palate


0.0

2.0

4.0

6.0

8.0

10.0

12.0

83-85

86-88

89-91

1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

10

20

30

40

50

60

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 37 42 37 51 44 51 63 49 44 43 52 53 N/10,000 5.7 6.3 5.7 7.7 6.8 7.8 9.8 7.8 7.0 6.9 8.3 8.4

Cleft Palate British Paediatric Association code 749.00 - 749.09

Fissure defect of the hard and / or soft palate usually positioned in the mid-line, but without clefting of the lips. This is considered to be a distinct birth defect, with different aetiology from cleft lip and palate together (see next section).

• The number of babies with cleft palate has fluctuated over the years, with no significant change in overall prevalence over the 16-year period (7.3/10,000 in 198394 and 7.8/10,000 in 199500).

• This is often associated with other birth defects and thus the occurrence of terminations, stillbirths and neonatal deaths in 19% of cases.

• There is a significant excess of female babies with this condition and it is less prevalent in twins.

68

Table 5.11.1 Cleft Palate, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval No. % No. % No. % No. % LL UL Total (n=859)* 555 112 87 105 8.0 7.2 9.0

Survived > 28 days 480 86.5 103 92.0 74 85.1 87 82.9 7.1 6.0 7.8

Neonatal death 40 7.2 2 1.8 6 6.9 8 7.6

Stillbirth 31 5.6 4 3.6 4 4.6 7 6.7

Termination < 20 wks 4 0.7 3 2.7 3 3.4 3 2.9

Sex Male 256 46.1 39 34.8 35 40.2 43 41.0 6.0 5.0 7.2

Female 298 53.7 73 65.2 51 58.6 61 58.1 10.1 8.7 11.7


Plurality

Singleton 536 96.6 112 100.0 86 98.9 102 97.1 8.2 7.3 9.2

Twin 16 2.9 0 0.0 1 1.1 3 2.9 3.5 1.0 9.0

Triplet 3 0.5 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • There is no significant association with maternal age, country of birth or region of residence.

69

Table 5.11.2 Cleft Palate, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=857)* 553 112 87 105 8.2 7.3 9.2

Maternal Age

<20 21 3.8 1 0.9 4 4.6 3 2.9 6.4 2.8 12.6

20-24 105 19.0 14 12.5 12 13.8 15 14.3 8.0 5.7 10.8

25-29 199 36.0 38 33.9 33 37.9 31 29.5 8.5 6.9 10.3

30-34 155 28.0 33 29.5 23 26.4 34 32.4 7.2 5.9 8.9

35-39 61 11.0 23 20.5 12 13.8 18 17.1 9.8 7.4 12.9

40+ 11 2.0 3 2.7 3 3.4 4 3.8 10.8 5.2 20.0

Unknown# 1 0.2 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 410 74.1 78 69.6 65 74.7 84 80.0 8.1 7.1 9.2

Oceania inc NZ 10 1.8 3 2.7 3 3.4 4 3.8 11.4 5.5 20.9

UK inc Eire 34 6.1 2 1.8 2 2.3 1 1.0 3.5 1.1 8.2

Europe 38 6.9 2 1.8 3 3.4 4 3.8 6.2 2.9 11.9

Middle East 18 3.3 3 2.7 1 1.1 1 1.0 5.5 1.8 12.9

Asia 30 5.4 19 17.0 10 11.5 10 9.5 11.2 7.9 15.3

Nth America 6 1.1 1 0.9 0 0.0 0 0.0 5.1 0.1 28.6

Sth America 0 0.0 1 0.9 0 0.0 0 0.0 4.7 0.1 26.3

Africa 4 0.7 3 2.7 3 3.4 1 1.0 14.5 5.8 29.9

Unknown# 3 0.5 0 0.0 0 0.0 0 0.0 N/A

Region

Barwon S W 35 6.3 6 5.4 3 3.4 6 5.7 6.0 3.3 9.8

Grampians 18 3.3 1 0.9 3 3.4 8 7.6 7.4 3.8 12.9

Loddon Mallee 42 7.6 4 3.6 7 8.0 3 2.9 6.3 3.4 10.5

Hume 32 5.8 5 4.5 3 3.4 9 8.6 8.9 5.2 14.3

Gippsland 39 7.1 7 6.3 5 5.7 11 10.5 12.8 8.1 19.2

Western Metro 77 13.9 15 13.4 17 19.5 14 13.3 9.2 6.7 12.3

Northern Metro 99 17.9 20 17.9 9 10.3 16 15.2 7.1 5.2 9.5

Eastern Metro 87 15.7 21 18.8 11 12.6 14 13.3 6.8 5.0 9.0

Southern Metro 117 21.2 32 28.6 27 31.0 22 21.0 9.6 7.7 12.0

Other 6 1.1 1 0.9 2 2.3 2 1.9 9.3 3.0 21.7

Unknown 1 0.2 0 0.0 0 0.0 0 0.0 n/a *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks

Table 5.11.3 Patterns of Birth Defects, Cleft Palate, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total

Isolated anomaly* 0 0 1 56 57 54.3Chromosomal 2 0 4 3 9 8.6 Other Same System (CNS) 0 0 0 0 0 0.0 Pierre Robin Sequence 0 0 0 16 16 15.2 Other Different Systems 1 7 3 12 23 21.9 Total 3 7 8 87 105 100.0* See p. 7 for the definition of an “isolated” anomaly.

70

5.12 Cleft Lip


0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

40

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 22 25 37 25 29 24 22 18 21 22 33 27 N/10,000 3.4 3.7 5.7 3.8 4.5 3.7 3.4 2.8 3.4 3.5 5.2 4.3

Cleft Lip British Paediatric Association code 749.10 - 749.19

Clefting of the upper lip, without clefting of the alveolar ridge and palate.

• Numbers have fluctuated each year with an overall prevalence of 3.8/10,000, almost half as

prevalent as cleft palate (7.8/10,000).

• This is an isolated birth defect in 82% of cases (compared with cleft palate, 54%).

• Isolated cleft lip is associated with stillbirth or neonatal death in 5% of cases.

• There are no significant associations with gender, plurality, maternal age, country of birth, or region of residence

71

Table 5.12.1 Cleft Lip, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 279 93.3 35 87.5 37 86.0 53 88.3 3.4 2.8 4.0

Neonatal death 4 1.3 0 0.0 1 2.3 1 1.7

Stillbirth 10 3.3 0 0.0 2 4.7 2 3.3

Termination < 20 wks 6 2.0 5 12.5 3 7.0 4 6.7

Sex Male 176 58.9 28 70.0 25 58.1 32 53.3 4.4 3.5 5.4

Female 120 40.1 12 30.0 17 39.5 28 46.7 3.1 2.4 4.1


Plurality

Singleton 292 97.7 39 97.5 43 100.0 60 100.0 3.9 3.3 4.6

Twin 7 2.3 1 2.5 0 0.0 0 0.0 0.9 0.0 4.9

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0


72

Table 5.12.2 Cleft Lip, 1999—2000, by Selected Maternal Characteristics Cases including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=442)* 299 40 43 60 3.8 3.3 4.5

Maternal Age

<20 13 4.3 1 2.5 2 4.7 4 6.7 5.6 2.2 11.5

20-24 52 17.4 7 17.5 5 11.6 7 11.7 3.7 2.2 5.8

25-29 109 36.5 11 27.5 14 32.6 19 31.7 3.7 2.7 4.9

30-34 90 30.1 15 37.5 10 23.3 21 35.0 3.7 2.7 4.9

35-39 33 11.0 2 5.0 5 11.6 6 10.0 1.5 0.8 2.6

40+ 1 0.3 3 7.5 7 16.3 3 5.0 14.1 7.5 24.1

Unknown# 1 0.3 1 2.5 0 0.0 0 0.0 N/A

Country of Birth

Australia 220 73.6 31 77.5 33 76.7 44 73.3 3.8 3.2 4.7

Oceania inc NZ 8 2.7 0 0.0 3 7.0 1 1.7 4.6 1.2 11.6

UK inc Eire 14 4.7 0 0.0 1 2.3 1 1.7 1.4 0.2 5.1

Europe 21 7.0 0 0.0 2 4.7 4 6.7 4.2 1.5 9.1

Middle East 7 2.3 1 2.5 1 2.3 0 0.0 2.2 0.3 8.0

Asia 18 6.0 3 7.5 2 4.7 6 10.0 3.2 1.6 5.6

Nth America 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Sth America 1 0.3 0 0.0 1 2.3 1 1.7 9.5 1.1 34.1

Africa 4 1.3 3 7.5 0 0.0 1 1.7 8.3 2.3 21.2

Unknown# 6 2.0 2 5.0 0 0.0 2 3.3 N/A

Region

Barwon S W 25 8.4 0 0.0 3 7.0 5 8.3 3.2 1.4 6.3

Grampians 18 6.0 1 2.5 3 7.0 1 1.7 3.1 1.0 7.2

Loddon Mallee 15 5.0 4 10.0 2 4.7 2 3.3 3.6 1.5 7.0

Hume 24 8.0 3 7.5 2 4.7 2 3.3 3.7 1.5 7.6

Gippsland 15 5.0 5 12.5 1 2.3 0 0.0 3.0 1.1 6.6

Western Metro 31 10.4 9 22.5 6 14.0 10 16.7 5.0 3.2 7.4

Northern Metro 54 18.1 5 12.5 11 25.6 14 23.3 4.7 3.2 6.7

Eastern Metro 58 19.4 5 12.5 10 23.3 11 18.3 3.8 2.5 5.6

Southern Metro 56 18.7 8 20.0 4 9.3 15 25.0 3.2 2.1 4.7

Other 2 0.7 0 0.0 1 2.3 0 0.0 1.9 0.0 10.4


Table 5.12.3 Patterns of Birth Defects, Cleft Lip, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


73

5.13 Cleft Lip and Palate


0.0

2.0

4.0

6.0

8.0

10.0

12.0

83-85

86-88

89-91

1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

10

20

30

40

50


Number 37 41 36 39 43 51 34 33 39 55 41 47 N/10,000 5.7 6.1 5.5 5.9 6.6 7.8 5.3 5.2 6.2 8.8 6.5 7.5

Cleft Lip and Palate British Paediatric Association code 749.20 - 749.29

Clefting of the upper lip, with clefting of the alveolar ridge and palate.

• The numbers are fluctuating each year, with an overall prevalence of 6.6/10,000.

• This condition is associated with stillbirths and neonatal deaths in 10% of cases. In 19992000, 10% were associated with pregnancy termination, probably indicating the presence of other more serious defects in the fetus.

• Another defect is present in 35% of cases.

• A highly significant excess of male babies is seen, as is a non-significant increased prevalence in twins.

• There is a significant association with maternal age 40 years and over compared with maternal age 25-34 years.

74

Table 5.13.1 Cleft Lip and Palate, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 387 76.9 49 73.1 66 70.2 70 79.5 5.0 4.3 5.8

Neonatal death 52 10.3 3 4.5 7 7.4 6 6.8

Stillbirth 47 9.3 4 6.0 10 10.6 3 3.4

Termination < 20 wks 17 3.4 11 16.4 11 11.7 9 10.2

Sex Male 310 61.6 42 62.7 66 70.2 53 60.2 8.3 7.1 9.7

Female 188 37.4 23 34.3 28 29.8 34 38.6 4.6 3.7 5.8


Plurality

Singleton 493 98.0 63 94.0 92 97.9 82 93.2 6.5 5.7 7.4

Twin 10 2.0 4 6.0 2 2.1 6 6.8 10.5 5.4 18.4

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • There are no significant associations with maternal country of birth or regions.

75

Table 5.13.2 Cleft Lip and Palate, 1999—2000, by Selected Maternal Characteristics Cases including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=751)* 502 67 94 88 6.7 5.9 7.6

Maternal Age

<20 24 4.8 4 6.0 3 3.2 4 4.5 8.8 4.4 15.7

20-24 104 20.7 7 10.4 12 12.8 14 15.9 6.4 4.4 9.0

25-29 170 33.9 21 31.3 32 34.0 20 22.7 6.1 4.8 7.7

30-34 138 27.5 23 34.3 29 30.9 28 31.8 6.4 5.1 8.1

35-39 55 11.0 8 11.9 14 14.9 16 18.2 7.0 4.9 9.6

40+ 8 1.6 4 6.0 4 4.3 6 6.8 15.2 8.3 25.5

Unknown# 3 0.6 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 347 69.1 54 80.6 79 84.0 75 85.2 7.4 6.4 8.5

Oceania inc NZ 8 1.6 2 3.0 3 3.2 4 4.5 10.2 4.7 19.5

UK inc Eire 33 6.6 2 3.0 3 3.2 3 3.4 5.7 2.4 11.1

Europe 32 6.4 1 1.5 2 2.1 0 0.0 2.1 0.4 6.1

Middle East 10 2.0 1 1.5 0 0.0 0 0.0 1.1 0.0 6.2

Asia 52 10.4 6 9.0 3 3.2 4 4.5 3.7 2.0 6.4

Nth America 3 0.6 0 0.0 1 1.1 0 0.0 5.1 0.1 28.6

Sth America 1 0.2 0 0.0 2 2.1 1 1.1 14.2 2.9 41.4

Africa 3 0.6 1 1.5 1 1.1 0 0.0 4.1 0.5 14.9

Unknown# 13 2.6 0 0.0 0 0.0 1 1.1 N/A

Region

Barwon S W 26 5.2 6 9.0 9 9.6 5 5.7 7.9 4.9 12.2

Grampians 24 4.8 1 1.5 5 5.3 3 3.4 5.5 2.5 10.5

Loddon Mallee 35 7.0 3 4.5 7 7.4 5 5.7 6.7 3.8 11.1

Hume 20 4.0 3 4.5 8 8.5 5 5.7 8.4 4.8 13.6

Gippsland 26 5.2 1 1.5 10 10.6 8 9.1 10.6 6.4 16.5

Western Metro 74 14.7 13 19.4 6 6.4 7 8.0 5.2 3.4 7.6

Northern Metro 83 16.5 13 19.4 9 9.6 12 13.6 5.3 3.7 7.5

Eastern Metro 91 18.1 12 17.9 23 24.5 15 17.0 7.4 5.5 9.7

Southern Metro 119 23.7 15 22.4 16 17.0 27 30.7 6.9 5.3 9.0

Other 3 0.6 0 0.0 1 1.1 1 1.1 3.7 0.5 13.4


Table 5.13.3 Patterns of Birth Defects, Cleft Lip and Palate, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


76

5.14 Oesophageal Atresia and/or Stenosis


0.01.02.0

3.04.05.06.0

7.08.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 19 21 22 31 27 23 23 27 33 20 18 20 N/10,000 3.0 3.1 3.4 4.7 4.2 3.5 3.6 4.3 5.3 3.2 2.9 3.2

Oesophageal Atresia and/or Stenosis British Paediatric Association code 750.30 - 750.38

Occlusion or narrowing of the oesophagus, with or without tracheo-oesphageal fistula.

• The prevalence of this defect has not changed overall, but fluctuates from year to year.

• In recent years, perinatal death occurred in 21% of cases.

• There is another birth defect present in 50% of cases.

• There is a non-significant excess of males with this condition.

• There is a highly significant five-fold increased prevalence in twins.

• A U-shaped maternal age effect (women aged <20 and >40 years have increased overall prevalence) is apparent, but not significant.

• There are no significant differences for women from different countries of birth or regions, except for a lower prevalence in Loddon Mallee Region compared with the metropolitan regions.

77

Table 5.14.1 Oesophageal Atresia and/or Stenosis, 19992000, by Selected Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval No. % No. % No. % No. % LL UL Total (n=416) 275 50 53 38 3.7 3.2 4.4

Survived > 28 days 200 72.7 32 64.0 39 73.6 30 78.9 2.7 2.2 3.3

Neonatal death 39 14.2 11 22.0 11 20.8 7 18.4

Stillbirth 31 11.3 6 12.0 2 3.8 1 2.6

Termination < 20 wks 5 1.8 1 2.0 1 1.9 0 0.0

Sex Male 164 59.6 16 32.0 33 62.3 27 71.1 3.9 3.1 4.9

Female 109 39.6 33 66.0 19 35.8 11 28.9 3.4 2.7 4.4


Plurality

Singleton 258 93.8 42 84.0 47 88.7 33 86.8 3.3 2.8 4.0

Twin 16 5.8 7 14.0 6 11.3 5 13.2 15.8 9.4 25.0

Triplet 1 0.4 1 2.0 0 0.0 0 0.0 20.6 0.5 114.8


78

Table 5.14.2 Oesophageal Atresia and/or Stenosis, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=414)* 275 49 53 37 3.7 3.2 4.4

Maternal Age

<20 15 5.5 2 4.1 3 5.7 2 5.4 5.6 2.2 11.5

20-24 36 13.1 8 16.3 10 18.9 2 5.4 3.9 2.4 6.0

25-29 122 44.4 17 34.7 17 32.1 12 32.4 3.8 2.8 5.1

30-34 68 24.7 12 24.5 11 20.8 10 27.0 2.7 1.8 3.7

35-39 27 9.8 10 20.4 9 17.0 10 27.0 5.3 3.6 7.7

40+ 6 2.2 0 0.0 3 5.7 1 2.7 4.3 1.2 11.1

Unknown# 1 0.4 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 204 74.2 38 77.6 38 71.7 28 75.7 3.7 3.0 4.5

Oceania inc NZ 2 0.7 1 2.0 2 3.8 0 0.0 3.4 0.7 10.0

UK inc Eire 22 8.0 2 4.1 2 3.8 1 2.7 3.5 1.1 8.2

Europe 15 5.5 3 6.1 4 7.5 2 5.4 6.2 2.9 11.9

Middle East 6 2.2 1 2.0 0 0.0 2 5.4 3.3 0.7 9.7

Asia 18 6.5 3 6.1 3 5.7 3 8.1 2.6 1.2 4.9

Nth America 1 0.4 0 0.0 0 0.0 0 0.0 0.0 N/A N/A

Sth America 2 0.7 1 2.0 2 3.8 0 0.0 14.2 2.9 41.4

Africa 1 0.4 0 0.0 0 0.0 1 2.7 2.1 0.1 11.5

Unknown# 4 1.5 0 0.0 2 3.8 0 0.0 N/A

Region

Barwon S W 17 6.2 0 0.0 4 7.5 4 10.8 3.2 1.4 6.3

Grampians 12 4.4 2 4.1 3 5.7 1 2.7 3.7 1.4 8.0

Loddon Mallee 21 7.6 0 0.0 0 0.0 1 2.7 0.4 0.0 2.5

Hume 9 3.3 2 4.1 0 0.0 1 2.7 1.6 0.3 4.6

Gippsland 17 6.2 2 4.1 1 1.9 1 2.7 2.2 0.6 5.7

Western Metro 29 10.5 8 16.3 9 17.0 4 10.8 4.2 2.6 6.4

Northern Metro 41 14.9 10 20.4 12 22.6 8 21.6 4.7 3.2 6.7

Eastern Metro 60 21.8 12 24.5 9 17.0 6 16.2 4.0 2.6 5.8

Southern Metro 66 24.0 12 24.5 15 28.3 11 29.7 4.5 3.2 6.2

Other 3 1.1 1 2.0 0 0.0 0 0.0 1.9 0.0 10.4


Table 5.14.3 Patterns of Birth Defects, Oesophageal Atresia and/or Stenosis, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


79

5.15 Anorectal Atresia and/or Stenosis


0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 24 25 28 34 25 31 36 32 35 33 24 18 N/10,000 3.7 3.7 4.3 5.1 3.8 4.8 5.6 5.1 5.6 5.3 3.8 2.9

Anorectal Atresia and/or Stenosis British Paediatric Association code 751.21 - 751.24

Imperforate anus or absence or narrowing of the communication between rectum and anus, with or without fistula to neighbouring organs.

• There was an increase in the overall prevalence of this condition up to 1997, but since then

there has been a marked decline to a lowest prevalence recorded in 2000 of 2.9/10,000.

• It is present as an isolated anomaly in only 26% of cases.

• There is a significant two-fold increased prevalence in males and in twins

• From 19952000, teenage women have been observed as having a significantly increased prevalence (11.2/10,000) compared with 25-29 year olds (4.5/10,000).

• There are no associations with maternal country of birth or region of residence

80

Table 5.15.1 Anorectal Atresia and/or Stenosis, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 199 67.9 40 58.8 42 61.8 27 64.3 2.9 2.4 3.5

Neonatal death 45 15.4 11 16.2 8 11.8 6 14.3

Stillbirth 35 11.9 12 17.6 8 11.8 5 11.9

Termination < 20 wks 14 4.8 5 7.4 10 14.7 4 9.5

Sex Male 181 61.8 43 63.2 40 58.8 28 66.7 5.7 4.7 6.9

Female 90 30.7 18 26.5 24 35.3 11 26.2 2.9 2.2 3.8


Plurality

Singleton 274 93.5 62 91.2 65 95.6 40 95.2 4.6 3.9 5.3

Twin 19 6.5 6 8.8 3 4.4 2 4.8 9.7 4.8 17.3

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0


81

Table 5.15.2 Anorectal Atresia and/or Stenosis, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=469)* 291 68 68 42 4.8 4.1 5.6

Maternal Age

<20 18 6.2 6 8.8 5 7.4 3 7.1 11.2 6.1 18.8

20-24 53 18.2 11 16.2 13 19.1 4 9.5 5.4 3.6 7.9

25-29 117 40.2 14 20.6 28 41.2 12 28.6 4.5 3.4 5.9

30-34 79 27.1 20 29.4 16 23.5 11 26.2 3.8 2.8 5.0

35-39 18 6.2 14 20.6 5 7.4 10 23.8 5.3 3.6 7.7

40+ 3 1.0 3 4.4 1 1.5 2 4.8 6.5 2.4 14.2

Unknown# 3 1.0 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 215 73.9 51 75.0 43 63.2 25 59.5 4.2 3.5 5.1

Oceania inc NZ 7 2.4 2 2.9 5 7.4 1 2.4 9.1 3.9 17.9

UK inc Eire 12 4.1 3 4.4 3 4.4 1 2.4 5.0 2.0 10.2

Europe 14 4.8 3 4.4 3 4.4 2 4.8 5.6 2.4 10.9

Middle East 4 1.4 1 1.5 1 1.5 1 2.4 3.3 0.7 9.7

Asia 20 6.9 7 10.3 8 11.8 10 23.8 7.2 4.6 10.6

Nth America 3 1.0 0 0.0 1 1.5 0 0.0 5.1 0.1 28.6

Sth America 0 0.0 0 0.0 2 2.9 0 0.0 9.5 1.1 34.1

Africa 2 0.7 1 1.5 0 0.0 1 2.4 4.1 0.5 14.9

Unknown# 14 4.8 0 0.0 2 2.9 1 2.4 N/A

Region

Barwon S W 16 5.5 4 5.9 6 8.8 1 2.4 4.4 2.2 7.8

Grampians 10 3.4 3 4.4 6 8.8 1 2.4 6.1 3.0 11.3

Loddon Mallee 22 7.6 2 2.9 5 7.4 2 4.8 4.0 1.8 7.6

Hume 17 5.8 3 4.4 2 2.9 2 4.8 3.7 1.5 7.6

Gippsland 24 8.2 2 2.9 4 5.9 1 2.4 3.9 1.6 8.0

Western Metro 39 13.4 13 19.1 14 20.6 9 21.4 7.2 5.0 10.0

Northern Metro 48 16.5 16 23.5 7 10.3 9 21.4 5.0 3.4 7.1

Eastern Metro 60 20.6 10 14.7 7 10.3 6 14.3 3.4 2.1 5.1

Southern Metro 51 17.5 14 20.6 16 23.5 9 21.4 4.6 3.3 6.3

Other 4 1.4 1 1.5 1 1.5 2 4.8 7.4 2.0 19.1


Table 5.15.3 Patterns of Birth Defects, Anorectal Atresia and/or Stenosis, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


82

5.16 Hypospadias


15.0

20.0

25.0

30.0

35.0

40.0

83-85

86-88

89-91

1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

020406080

100120140160180200220240


Number 185 187 195 233 194 209 219 235 197 216 219 180 N/10,000 28.7 27.9 29.8 35.1 29.9 32.1 34.2 37.2 31.5 34.6 34.8 28.6

Hypospadias British Paediatric Association code 752.60

Abnormal opening of the male urethra upon the undersurface of the penis.

• There was a marked increase in notifications of hypospadias in 1989. Since 1989 over 180

cases each year reported to the BDR, compared with 100 or so before 1988. Repair of this defect has been done at 6 - 18 months of age since the mid 1980s, however prior to that time repair was done at 3 - 4 years of age and notification may not have been made. The earlier management, plus our current system of receiving inpatient listings from the Royal Children’s Hospital, may account for more notifications to the BDR in recent years.

• The overall prevalence for 19992000 is 33.5/10000, and the linear increase since 1983 has been highly significant (χ2 for linear trend = 106.4, p<0.0001), however there has been no increase since 1996.

• As there are few associated perinatal deaths (2%), it is likely that hypospadias is rarely associated with major (lethal) malformations. It occurs as an isolated defect in 88% of cases.

• There is a significant increased prevalence in twins compared with singletons.

• There is no linear trend with maternal age.

83

Table 5.16.1 Hypospadias, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval No. % No. % No. % No. % LL UL Total (n=3,148)* 1,882 454 413 399 33.5 31.7 35.3

Survived > 28 days 1,836 97.6 446 98.2 409 99.0 390 97.7 33.4 31.6 35.3

Neonatal death 34 1.8 4 0.9 3 0.7 6 1.5

Stillbirth 10 0.5 3 0.7 1 0.2 2 0.5

Termination < 20 wks 2 0.1 1 0.2 0 0.0 1 0.3

Sex Male 1,874 99.6 453 99.8 413 100.0 399 100.0 65.0 61.4 68.6

Female 0 0.0 0 0.0 0 0.0 0 0.0


Plurality

Singleton 1,820 96.7 436 96.0 387 93.7 380 95.2 32.9 31.0 34.7

Twin 58 3.1 16 3.5 25 6.1 17 4.3 50.9 39.0 66.3

Triplet 3 0.2 2 0.4 1 0.2 2 0.5 103.1 33.4 240.2

Other 1 0.1 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • There is significant variation in prevalence with maternal country of birth. Women of Asian

background have a significantly reduced prevalence compared to almost all other ethnic groups of women.

• There are no significant regional variations.

84

Table 5.16.2 Hypospadias, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=3,138)* 1,876 453 412 397 33.9 32.1 35.8

Maternal Age

<20 98 5.2 16 3.5 15 3.6 20 5.0 40.8 30.7 54.1

20-24 387 20.6 75 16.6 66 16.0 50 12.6 37.1 32.1 42.9

25-29 710 37.8 142 31.3 141 34.2 126 31.7 34.0 30.7 37.3

30-34 498 26.5 146 32.2 121 29.4 128 32.2 31.8 28.8 35.1

35-39 159 8.5 64 14.1 58 14.1 62 15.6 33.9 29.3 39.2

40+ 23 1.2 10 2.2 11 2.7 11 2.8 34.7 23.7 49.1

Unknown# 1 0.1 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 1,461 77.9 372 82.1 328 79.6 319 80.4 36.3 34.1 38.5

Oceania inc NZ 38 2.0 9 2.0 5 1.2 6 1.5 22.8 13.9 35.0

UK inc Eire 98 5.2 15 3.3 22 5.3 16 4.0 37.5 28.3 49.4

Europe 131 7.0 17 3.8 13 3.2 14 3.5 30.5 22.2 41.0

Middle East 50 2.7 12 2.6 17 4.1 12 3.0 45.3 32.5 61.4

Asia 60 3.2 19 4.2 19 4.6 18 4.5 16.1 12.2 21.0

Nth America 6 0.3 4 0.9 1 0.2 3 0.8 41.1 17.7 80.9

Sth America 4 0.2 0 0.0 0 0.0 2 0.5 9.5 1.1 34.1

Africa 24 1.3 5 1.1 7 1.7 7 1.8 39.3 23.7 61.4

Unknown# 4 0.2 0 0.0 0 0.0 0 0.0 N/A

Region

Barwon S W 142 7.6 33 7.3 28 6.8 25 6.3 34.2 27.5 42.4

Grampians 87 4.6 25 5.5 21 5.1 14 3.5 36.9 28.4 47.8

Loddon Mallee 108 5.8 21 4.6 34 8.3 20 5.0 33.5 26.5 42.3

Hume 119 6.3 18 4.0 17 4.1 28 7.1 33.0 25.6 42.5

Gippsland 110 5.9 21 4.6 19 4.6 20 5.0 33.3 25.7 43.2

Western Metro 255 13.6 59 13.0 48 11.7 44 11.1 30.2 25.7 35.5

Northern Metro 329 17.5 104 23.0 90 21.8 57 14.4 39.5 34.8 44.8

Eastern Metro 335 17.9 71 15.7 76 18.4 68 17.1 31.6 27.6 36.2

Southern Metro 371 19.8 96 21.2 77 18.7 104 26.2 32.9 29.2 37.1

Other 20 1.1 5 1.1 2 0.5 17 4.3 44.7 28.6 66.5


Table 5.16.3 Patterns of Birth Defects, Hypospadias, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


85

5.17 Renal Agenesis and Dysgenesis


0.0

2.0

4.0

6.0

8.0

10.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

10

20

30

40

50

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 36 24 43 23 22 42 47 51 28 43 47 42 N/10,000 5.6 3.6 6.6 3.5 3.4 6.4 7.3 8.1 4.5 6.9 7.5 6.7

Renal Agenesis/Dysgenesis British Paediatric Association code 753.00 - 753.01

Bilateral or unilateral absence of the kidneys or severe dysplasia.

Unilateral disease is very different from bilateral, but the figures here include both conditions.

• There are marked annual fluctuations in numbers of babies with renal agenesis. The overall

prevalence has significantly increased to 6.8/10,000 in 19952000 from 4.8/10,000 in 19831994 (χ2 for linear trend = 15.1, p = 0.0001)

• Some of the reduction in neonatal deaths and stillbirths may be due to the more severe cases being identified in utero and being represented amongst the increased proportion of terminations.

• The increased overall prevalence in males is significant.

• There is no significant association with maternal age or region of residence.

86

Table 5.17.1 Renal Agenesis and Dysgenesis, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 121 33.0 58 28.6 36 50.7 40 44.9 2.8 2.3 3.4

Neonatal death 140 38.1 16 16.3 15 21.1 19 21.3

Stillbirth 74 20.2 14 14.3 10 14.1 13 14.6

Termination < 20 wks 32 8.7 10 10.2 10 14.1 17 19.1

Sex Male 235 64.0 72 73.5 46 64.8 53 59.6 8.8 7.6 10.3

Female 111 30.2 20 20.4 23 32.4 25 28.1 3.7 2.9 4.7


Plurality

Singleton 348 94.8 93 94.9 67 94.4 85 95.5 6.7 5.9 7.6

Twin 19 5.2 5 5.1 4 5.6 4 4.5 11.4 6.1 19.5

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0 #N/A #N/A

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • Asian-born women have a significantly lower prevalence of babies with this condition,

compared to Australian-, North American- and Middle Eastern-born women.

87

Table 5.17.2 Renal Agenesis and Dysgenesis, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=624)* 366 98 71 89 6.9 6.1 7.9

Maternal Age

<20 23 6.3 5 5.1 3 4.2 3 3.4 8.8 4.4 15.7

20-24 82 22.4 15 15.3 13 18.3 9 10.1 7.2 5.1 9.9

25-29 122 33.3 29 29.6 26 36.6 28 31.5 6.9 5.5 8.6

30-34 113 30.9 26 26.5 18 25.4 24 27.0 5.5 4.3 7.0

35-39 18 4.9 19 19.4 9 12.7 21 23.6 9.0 6.7 12.0

40+ 5 1.4 4 4.1 2 2.8 4 4.5 10.8 5.2 20.0

Unknown# 3 0.8 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 256 69.9 75 76.5 59 83.1 67 75.3 7.2 6.2 8.2

Oceania inc NZ 4 1.1 4 4.1 1 1.4 1 1.1 6.8 2.5 14.9

UK inc Eire 16 4.4 5 5.1 2 2.8 2 2.2 6.4 2.9 12.1

Europe 33 9.0 2 2.0 1 1.4 2 2.2 3.5 1.1 8.1

Middle East 11 3.0 5 5.1 2 2.8 4 4.5 12.1 6.1 21.7

Asia 14 3.8 5 5.1 1 1.4 4 4.5 2.9 1.4 5.3

Nth America 1 0.3 0 0.0 3 4.2 1 1.1 20.5 5.6 52.6

Sth America 1 0.3 0 0.0 1 1.4 2 2.2 14.2 2.9 41.4

Africa 5 1.4 1 1.0 0 0.0 4 4.5 10.4 3.4 24.1

Unknown# 25 6.8 1 1.0 1 1.4 2 2.2 N/A

Region

Barwon S W 20 5.5 10 10.2 9 12.7 6 6.7 9.9 6.4 14.7

Grampians 10 2.7 8 8.2 3 4.2 4 4.5 9.2 5.2 15.2

Loddon Mallee 18 4.9 4 4.1 7 9.9 3 3.4 6.3 3.4 10.5

Hume 20 5.5 3 3.1 4 5.6 6 6.7 6.8 3.6 11.7

Gippsland 20 5.5 7 7.1 3 4.2 4 4.5 7.8 4.2 13.1

Western Metro 51 13.9 14 14.3 10 14.1 15 16.9 7.8 5.5 10.7

Northern Metro 75 20.5 19 19.4 10 14.1 22 24.7 8.0 6.0 10.6

Eastern Metro 69 18.9 11 11.2 11 15.5 10 11.2 4.7 3.2 6.7

Southern Metro 74 20.2 22 22.4 12 16.9 18 20.2 6.2 4.7 8.2

Other 8 2.2 0 0.0 2 2.8 1 1.1 5.6 1.1 16.3


Table 5.17.3 Patterns of Birth Defects, Renal Agenesis and Dysgenesis, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


88

5.18 Cystic Kidney Disease


0.0

2.0

4.0

6.0

8.0

10.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

40

45

50

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 26 32 30 36 33 31 40 44 46 39 48 44 N/10,000 4.0 4.8 4.6 5.4 5.1 4.8 6.3 7.0 7.3 6.3 7.6 7.0

Cystic Kidney Disease British Paediatric Association code 753.10 - 753.18

This covers a wide range of birth defects with renal cysts of varying size and extent, occurring bilaterally or unilaterally. Polycystic and multicystic kidney disease are both included.

• There has been a significant increase in overall prevalence of babies with this condition, from

4.0/1000 in 19831994 to 6.9/1000 in 19952000 (χ2 for linear trend = 49.0, p <0.0001).

• The number of babies that survive at least 28 days has increased from 47% to 65%. This may be due to increased ascertainment of milder cases. There are now over 40 cases reported each year.

• Again there is a significant excess of males with renal disease, and a significant increased prevalence in twins.

• 22% of cases are associated with another renal defect.

89

Table 5.18.1 Cystic Kidney, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 147 47.9 50 59.5 59 69.4 60 65.2 4.5 3.9 5.3

Neonatal death 86 28.0 9 10.7 9 10.6 8 8.7

Stillbirth 45 14.7 9 10.7 7 8.2 13 14.1

Termination < 20 wks 29 9.4 16 19.0 10 11.8 11 12.0

Sex Male 182 59.3 53 63.1 53 62.4 55 59.8 8.3 7.1 9.7

Female 120 39.1 29 34.5 31 36.5 36 39.1 5.2 4.3 6.4


Plurality

Singleton 291 94.8 80 95.2 81 95.3 84 91.3 6.7 5.9 7.6

Twin 15 4.9 4 4.8 4 4.7 8 8.7 14.1 8.0 22.8

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0 #N/A #N/A

Other 1 0.3 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • There is no significant association with maternal age, country of birth, or region of residence.

90

Table 5.18.2 Cystic Kidney, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=567)* 307 84 85 91 7.0 6.2 7.9

Maternal Age

<20 17 5.5 2 2.4 3 3.5 4 4.4 7.2 3.3 13.7

20-24 53 17.3 16 19.0 13 15.3 13 14.3 8.2 5.9 11.0

25-29 117 38.1 26 31.0 29 34.1 24 26.4 6.6 5.2 8.2

30-34 85 27.7 25 29.8 26 30.6 35 38.5 6.9 5.6 8.6

35-39 26 8.5 13 15.5 11 12.9 15 16.5 7.2 5.1 9.8

40+ 1 0.3 2 2.4 3 3.5 0 0.0 5.4 1.8 12.6

Unknown# 8 2.6 0 0.0 0 0.0 0 0.0

Country of Birth

Australia 230 74.9 58 69.0 70 82.4 66 72.5 6.9 6.0 8.0

Oceania inc NZ 4 1.3 3 3.6 1 1.2 3 3.3 8.0 3.2 16.4

UK inc Eire 14 4.6 6 7.1 3 3.5 1 1.1 7.1 3.4 13.0

Europe 17 5.5 5 6.0 2 2.4 2 2.2 6.2 2.9 11.9

Middle East 7 2.3 0 0.0 1 1.2 4 4.4 5.5 1.8 12.9

Asia 11 3.6 7 8.3 4 4.7 9 9.9 5.7 3.5 8.8

Nth America 0 0.0 0 0.0 1 1.2 1 0.0 5.1 0.1 28.6

Sth America 1 0.3 2 2.4 0 0.0 1 1.1 14.2 2.9 41.4

Africa 1 0.3 2 2.4 0 0.0 3 3.3 10.4 3.4 24.1

Unknown# 22 7.2 1 1.2 3 3.5 1 1.1

Region

Barwon S W 21 6.8 2 2.4 3 3.5 6 6.6 4.4 2.2 7.8

Grampians 15 4.9 2 2.4 6 7.1 2 2.2 6.1 3.0 11.3

Loddon Mallee 19 6.2 8 9.5 9 10.6 6 6.6 10.3 6.5 15.4

Hume 19 6.2 4 4.8 4 4.7 2 2.2 5.2 2.5 9.6

Gippsland 12 3.9 4 4.8 4 4.7 4 4.4 6.7 3.4 11.7

Western Metro 54 17.6 14 16.7 9 10.6 19 20.9 8.4 6.0 11.4

Northern Metro 56 18.2 27 32.1 12 14.1 20 22.0 9.3 7.1 12.1

Eastern Metro 60 19.5 8 9.5 18 21.2 15 16.5 6.0 4.3 8.2

Southern Metro 46 15.0 13 15.5 20 23.5 16 17.6 5.8 4.3 7.7

Other 4 1.3 2 2.4 0 0.0 1 1.2 5.6 1.1 16.3

Unknown 1 0.3 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks

Table 5.18.3 Patterns of Birth Defects, Cystic Kidney, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


91

5.19 Obstructive Defects of Renal Pelvis


0.0

10.0

20.0

30.0

40.0

50.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

020406080

100120140160180200220240260280

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 58 93 105 102 112 171 141 164 178 252 279 241 N/10,000 9.0 13.9 16.1 15.3 17.2 26.2 22.0 25.9 28.4 40.4 44.3 38.4

Obstructive Defects of Renal Pelvis British Paediatric Association code 753.20 - 753.29

This heterogeneous group includes hydronephrosis and any other defect that results in dilatation of the renal collecting system, bilaterally or unilaterally.

• Ultrasound in pregnancy has identified a large number of babies with this condition. Where

possible, this diagnosis is confirmed postnatally, before inclusion in the BDR. Further increase in prevalence was seen in 1999 when almost 280 cases were reported. The overall prevalence has increased three-fold from 10.5/10,000 in 19831994 to 32.9/10,000 in 19952000. (Χ2 for linear trend = 930, p<0.0001).

• There is nearly a three-fold increased risk for males compared with females. This difference is apparent even when analysing the data year by year (as shown in the previous report). This was done to ensure that an excess of males was not caused by recent diagnoses in male babies less than one year of age; males are often investigated for this condition after only one urinary tract infection, while females may have several before such investigation

92

Table 5.19.1 Obstructive Defects of Renal Pelvis, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence

Interval No. % No. % No. % No. % LL UL Total (n=2,100)* 845 305 430 520 33.2 31.4 35.0

Survived > 28 days 701 83.0 275 90.2 389 90.5 485 93.3 30.9 29.1 32.6

Neonatal death 92 10.9 13 4.3 16 3.7 12 2.3

Stillbirth 35 4.1 7 2.3 18 4.2 17 3.3

Termination < 20 wks 17 2.0 10 3.3 7 1.6 6 1.2

Sex Male 605 71.6 227 74.4 318 74.0 377 72.5 47.5 44.4 50.5

Female 232 27.5 77 25.2 111 25.8 141 27.1 18.0 16.1 20.0


Plurality

Singleton 802 94.9 296 97.0 415 96.5 500 96.2 33.1 31.2 34.9

Twin 43 5.1 9 3.0 14 3.3 20 3.8 37.8 27.3 50.9

Triplet 0 0.0 0 0.0 1 0.2 0 0.0 20.6 0.5 114.8

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • In 19992000, less than 5% died in the perinatal period, association with lethal birth defects

being uncommon. It is associated with other system defects in 26% of cases.

• Women born in the Middle East have a significantly higher prevalence of babies with this condition, compared to Australian-, UK- and Asian-born women.

• Marked differences in prevalence between regions are observed with Barwon and three of the four Metropolitan regions having significantly higher rates than Gippsland.

93

Table 5.19.2 Obstructive Defects of Renal Pelvis, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=2,091) 840 304 429 518 33.6 31.8 35.5

Maternal Age

<20 34 4.0 12 3.9 18 4.2 16 3.1 36.8 26.9 49.1

20-24 150 17.9 42 13.8 70 16.3 85 16.4 38.3 33.2 44.1

25-29 319 38.0 113 37.2 136 31.7 168 32.4 34.7 31.4 38.0

30-34 239 28.5 92 30.3 128 29.8 162 31.3 30.7 27.8 34.0

35-39 76 9.0 41 13.5 67 15.6 74 14.3 33.5 28.9 38.9

40+ 20 2.4 3 1.0 10 2.3 13 2.5 28.2 18.4 41.5

Unknown# 2 0.2 1 0.3 0 0.0 0 0.0 N/A

Country of Birth

Australia 623 74.2 210 69.1 316 73.7 390 75.3 32.6 30.5 34.7

Oceania inc NZ 21 2.5 9 3.0 14 3.3 12 2.3 39.8 27.8 55.3

UK inc Eire 47 5.6 13 4.3 13 3.0 18 3.5 31.1 22.6 41.8

Europe 44 5.2 13 4.3 24 5.6 21 4.1 40.2 30.8 52.4

Middle East 24 2.9 15 4.9 19 4.4 19 3.7 58.5 44.2 77.2

Asia 47 5.6 33 10.9 31 7.2 50 9.7 32.7 27.1 39.4

Nth America 3 0.4 1 0.3 4 0.9 3 0.6 41.1 17.7 80.9

Sth America 5 0.6 4 1.3 2 0.5 1 0.2 33.1 13.3 68.1

Africa 13 1.5 5 1.6 4 0.9 4 0.8 26.9 14.3 46.0

Unknown# 13 1.5 1 0.3 2 0.5 0 0.0 N/A

Region

Barwon S W 68 8.1 28 9.2 30 7.0 32 6.2 35.7 28.9 44.1

Grampians 49 5.8 9 3.0 15 3.5 14 2.7 23.4 16.5 32.1

Loddon Mallee 43 5.1 28 9.2 16 3.7 27 5.2 31.7 25.0 40.3

Hume 46 5.5 11 3.6 24 5.6 41 7.9 39.8 31.6 50.2

Gippsland 46 5.5 8 2.6 14 3.3 12 2.3 18.9 13.1 26.4

Western Metro 103 12.3 44 14.5 46 10.7 75 14.5 33.0 28.2 38.5

Northern Metro 151 18.0 56 18.4 105 24.5 109 21.0 42.5 37.6 47.9

Eastern Metro 155 18.5 51 16.8 58 13.5 65 12.5 25.6 22.0 29.8

Southern Metro 166 19.8 66 21.7 108 25.2 114 22.2 34.2 30.4 38.5

Other 12 1.4 3 1.0 13 3.0 29 5.6 83.7 61.0 112.2


Table 5.19.3 Patterns of Birth Defects, Obstructive Defects of Renal Pelvis, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


94

5.20 Congenital Dislocation of Hip


15.0

20.0

25.0

30.0

35.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

020

406080

100

120140160180

200220

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Survived > 28 days Liveborn, neonatal deathStillborn Termination< 20 w eeks

Number 209 225 224 205 193 160 170 186 149 176 166 163 N/10,000 32.5 33.6 34.3 30.8 29.7 24.5 26.6 29.4 23.8 28.2 26.4 25.9

Congenital Dislocation of the Hip British Paediatric Association code 754.30

The femoral head is displaced (or displaceable) from the acetabulum of the pelvis.

This is not to be confused with ‘clicky hips’ which are not included in the BDR.

This is sometimes referred to as Developmental Hip Dysplasia. • This is one of the more commonly reported conditions, the number reported having remained

at over 150 cases per year since 1983 (except for 1997 when there were 149 cases). However there has been a significant decline in prevalence from 29.4/10,000 in 19831994 to 26.7/10,000 in 19952000 (χ2 for linear trend = 6.99, p=0.008).

• There is almost no associated stillbirth or neonatal death and this occurs as an isolated defect in 92% of cases.

• Female babies have an almost four-fold increased risk and a prevalence of 41.0/10,000 births.

• There is a lower prevalence in twins as has been reported previously.

95

Table 5.20.1 Congenital Dislocation of Hip, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 2,240 99.3 353 99.2 320 98.5 327 99.4 26.9 25.2 28.5

Neonatal death 14 0.6 1 0.3 3 0.9 2 0.6

Stillbirth 1 0.0 1 0.3 2 0.6 0 0.0

Termination < 20 wks 0 0.0 1 0.3 0 0.0 0 0.0

Sex Male 482 21.4 92 25.8 73 22.5 85 25.8 12.9 11.4 14.6

Female 1,771 78.5 264 74.2 252 77.5 244 74.2 41.5 38.5 44.4


Plurality

Singleton 2,240 99.3 352 98.9 324 99.7 324 98.5 27.3 25.6 29.0

Twin 15 0.7 4 1.1 1 0.3 4 1.2 7.9 3.6 15.0

Triplet 0 0.0 0 0.0 1 0.3 0 0.0 0.0

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • A significantly lower prevalence of babies with CDH was seen in Asian-born women,

compared to Australian- and UK-born women.

• Women living in Gippsland have a significantly higher prevalence compared with women living everywhere else.

96

Table 5.20.2 Congenital Dislocation of Hip, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=3,264)* 2,254 356 325 329 27.2 25.5 28.8

Maternal Age

<20 78 3.5 11 3.1 11 3.4 14 4.3 28.8 20.2 39.8

20-24 372 16.5 36 10.1 44 13.5 26 7.9 20.6 17.0 25.0

25-29 917 40.7 119 33.4 107 32.9 106 32.2 27.6 24.8 30.8

30-34 650 28.8 130 36.5 116 35.7 127 38.6 30.0 27.1 33.3

35-39 216 9.6 54 15.2 43 13.2 45 13.7 26.2 22.1 30.9

40+ 20 0.9 6 1.7 4 1.2 11 3.3 22.8 14.1 34.9

Unknown# 1 0.0 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 1,845 81.9 273 76.7 263 80.9 276 83.9 28.9 26.9 30.9

Oceania inc NZ 31 1.4 4 1.1 8 2.5 5 1.5 19.3 11.3 30.9

UK inc Eire 139 6.2 24 6.7 12 3.7 10 3.0 32.5 23.8 43.5

Europe 104 4.6 12 3.4 10 3.1 10 3.0 22.2 15.2 31.4

Middle East 31 1.4 10 2.8 2 0.6 3 0.9 16.6 9.3 27.3

Asia 70 3.1 21 5.9 25 7.7 16 4.9 17.8 13.7 22.9

Nth America 12 0.5 3 0.8 3 0.9 1 0.3 35.9 14.4 74.0

Sth America 3 0.1 1 0.3 0 0.0 3 0.9 18.9 5.1 48.4

Africa 15 0.7 6 1.7 2 0.6 5 1.5 26.9 14.3 46.0

Unknown# 4 0.2 2 0.6 0 0.0 0 0.0 N/A

Region

Barwon S W 202 9.0 23 6.5 16 4.9 23 7.0 24.6 19.0 31.8

Grampians 137 6.1 14 3.9 8 2.5 18 5.5 24.6 17.6 33.4

Loddon Mallee 170 7.5 21 5.9 14 4.3 10 3.0 20.1 14.7 26.9

Hume 114 5.1 17 4.8 18 5.5 17 5.2 27.3 20.6 36.0

Gippsland 147 6.5 25 7.0 21 6.5 35 10.6 45.0 36.0 56.3

Western Metro 186 8.3 45 12.6 42 12.9 37 11.2 24.8 20.7 29.7

Northern Metro 293 13.0 52 14.6 41 12.6 44 13.4 21.5 18.2 25.6

Eastern Metro 400 17.7 56 15.7 73 22.5 64 19.5 28.4 24.6 32.8

Southern Metro 581 25.8 95 26.7 87 26.8 74 22.5 30.4 26.9 34.4

Other 24 1.1 8 2.2 5 1.5 7 2.1 37.2 22.7 57.3


Table 5.20.3 Patterns of Birth Defects, Congenital Dislocation of Hips, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


97

5.21 Limb Reduction Defects


0.0

2.0

4.0

6.0

8.0

10.0

12.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

10

20

30

40

50

60

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 38 36 41 46 47 33 45 61 46 33 47 31 N/10,000 5.9 5.4 6.3 6.9 7.2 5.1 7.0 9.6 7.3 5.3 7.5 4.9

Limb Reduction Defects British Paediatric Association code 755.20 - 755.49

There is a wide range of severity from partial absence of a phalanx to complete absence of a major skeletal structure such as a whole limb. These may for other purposes be analysed in groups: transverse, longitudinal, intercalary, multiple or unspecified.

• 30-50 cases of limb reduction defects are reported to the BDR each year, except for a peak in 1996 when over 60 cases were notified. Prevalence fluctuates from year to year and there is no significant trend.

• Approximately 18% of pregnancies are terminated when this defect is recognised in a fetus. It is often associated with other birth defects (60%) and 27% die in the perinatal period.

• There is a significantly increased prevalence in males and a non-significant increase in twins.

• There is a non-significant association with maternal age.

• The only significant association with maternal country of birth was for women born in UK/Eire who have a higher prevalence of affected babies than Australian-born women.

98

Table 5.21.1 Limb Reduction Defects, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 305 66.3 63 59.4 45 57.0 43 55.1 4.1 3.4 4.8

Neonatal death 48 10.4 7 6.6 7 8.9 5 6.4

Stillbirth 69 15.0 21 19.8 13 16.5 16 20.5

Termination < 20 wks 38 8.3 15 14.2 14 17.7 14 17.9

Sex Male 242 52.6 60 56.6 44 55.7 46 59.0 7.7 6.6 9.1

Female 207 45.0 39 36.8 32 40.5 27 34.6 5.3 4.4 6.5


Plurality

Singleton 443 96.3 97 91.5 74 93.7 75 96.2 6.7 5.9 7.6

Twin 16 3.5 7 6.6 5 6.3 2 2.6 12.3 6.7 20.7

Triplet 1 0.2 2 1.9 0 0.0 0 0.0 41.2 5.0 148.9


99

Table 5.21.2 Limb Reduction Defects, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=723)* 460 106 79 78 7.1 6.3 8.0

Maternal Age

<20 22 4.8 4 3.8 4 5.1 3 3.8 8.8 4.4 15.7

20-24 90 19.6 19 17.9 7 8.9 12 15.4 7.4 5.2 10.1

25-29 177 38.5 31 29.2 22 27.8 25 32.1 6.5 5.2 8.1

30-34 122 26.5 31 29.2 27 34.2 25 32.1 6.7 5.4 8.3

35-39 35 7.6 17 16.0 15 19.0 10 12.8 7.7 5.6 10.5

40+ 11 2.4 4 3.8 3 3.8 3 3.8 10.8 5.2 20.0

Unknown# 3 0.7 0 0.0 1 1.3 0 0.0 N/A

Country of Birth

Australia 332 72.2 75 70.8 50 63.3 60 76.9 6.6 5.7 7.6

Oceania inc NZ 7 1.5 3 2.8 1 1.3 3 3.8 8.0 3.2 16.4

UK inc Eire 25 5.4 8 7.5 7 8.9 4 5.1 13.4 8.1 21.0

Europe 33 7.2 8 7.5 1 1.3 3 3.8 8.3 4.3 14.6

Middle East 8 1.7 2 1.9 5 6.3 1 1.3 8.8 3.8 17.4

Asia 25 5.4 8 7.5 10 12.7 6 7.7 6.9 4.4 10.3

Nth America 1 0.2 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Sth America 0 0.0 1 0.9 0 0.0 0 0.0 4.7 0.1 26.3

Africa 2 0.4 0 0.0 1 1.3 0 0.0 2.1 0.1 11.5

Unknown# 27 5.9 1 0.9 4 5.1 1 1.3 N/A

Region

Barwon S W 36 7.8 8 7.5 7 8.9 0 0.0 6.0 3.3 9.8

Grampians 15 3.3 8 7.5 3 3.8 3 3.8 8.6 4.7 14.5

Loddon Mallee 25 5.4 7 6.6 5 6.3 3 3.8 6.7 3.8 11.1

Hume 28 6.1 1 0.9 3 3.8 3 3.8 3.7 1.5 7.6

Gippsland 19 4.1 4 3.8 3 3.8 5 6.4 6.7 3.4 11.7

Western Metro 62 13.5 14 13.2 13 16.5 13 16.7 8.0 5.7 10.9

Northern Metro 85 18.5 20 18.9 12 15.2 16 20.5 7.6 5.6 10.0

Eastern Metro 92 20.0 21 19.8 13 16.5 13 16.7 6.9 5.1 9.2

Southern Metro 90 19.6 22 20.8 16 20.3 20 25.6 6.9 5.3 9.0

Other 8 1.7 1 0.9 3 3.8 2 2.6 11.2 4.1 24.3


Table 5.21.3 Patterns of Birth Defects, Limb Reduction Defects, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


100

5.22 Diaphragmatic Hernia


0.01.02.03.04.05.06.07.08.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 10 33 31 27 18 25 34 26 19 25 28 13 N/10,000 1.6 4.9 4.7 4.1 2.3 3.8 5.3 4.1 3.0 4.0 4.4 2.1

Diaphragmatic Hernia British Paediatric Association code 756.61

Herniation of the abdominal organs into the thorax through a defect in the diaphragm.

• Non-significant fluctuations are seen each year in the prevalence of this condition, but there

was a significantly lower prevalence observed in 2000. The overall prevalence for 19952000 is 3.8/10,000 compared to 3.3/10,000 for 1983-1994.

• The annual proportion that have been liveborn, but died as neonates, has declined from 39% to 29% in 19992000. This may reflect identification of the problem prenatally by ultrasound and preparation for acute management at the time of birth, resulting in better neonatal outcome.

• There is no significant difference in prevalence between male and females or twins and singletons.

• The increased prevalence in women 35 years and over is not significant.

101

Table 5.22.1 Diaphragmatic Hernia, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 107 42.3 32 53.3 18 40.9 24 58.5 2.0 1.6 2.5

Neonatal death 98 38.7 15 25.0 15 34.1 9 22.0

Stillbirth 32 12.6 9 15.0 5 11.4 3 7.3

Termination < 20 wks 16 6.3 4 6.7 6 13.6 5 12.2

Sex Male 129 51.0 32 53.3 23 52.3 22 53.7 4.0 3.1 5.0

Female 122 48.2 28 46.7 20 45.5 19 46.3 3.7 2.9 4.7


Plurality

Singleton 248 98.0 57 95.0 44 100.0 40 97.6 3.9 3.3 4.6

Twin 5 2.0 3 5.0 0 0.0 1 2.4 3.5 1.0 9.0

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • There is no significant maternal country of birth or regional association.

102

Table 5.22.2 Diaphragmatic Hernia, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% confidence

Interval


Total (n=398)* 253 60 44 41 3.9 3.3 4.6

Maternal Age

<20 6 2.4 2 3.3 1 2.3 2 4.9 4.0 1.3 9.3

20-24 52 20.6 9 15.0 8 18.2 3 7.3 3.9 2.4 6.0

25-29 88 34.8 16 26.7 14 31.8 11 26.8 3.4 2.4 4.6

30-34 70 27.7 19 31.7 11 25.0 12 29.3 3.4 2.4 4.6

35-39 31 12.3 11 18.3 9 20.5 10 24.4 5.5 3.7 7.9

40+ 4 1.6 3 5.0 1 2.3 3 7.3 11.3 4.5 23.2

Unknown# 2 0.8 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 173 68.4 48 80.0 35 79.5 32 78.0 4.1 3.4 4.9

Oceania inc NZ 2 0.8 3 5.0 1 2.3 1 2.4 5.7 1.8 13.3

UK inc Eire 20 7.9 3 5.0 3 6.8 1 2.4 5.0 2.0 10.2

Europe 19 7.5 1 1.7 0 0.0 2 4.9 2.1 0.4 6.1

Middle East 3 1.2 3 5.0 0 0.0 0 0.0 3.3 0.7 9.7

Asia 13 5.1 2 3.3 3 6.8 4 9.8 2.6 1.2 4.9

Nth America 1 0.4 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Sth America 3 1.2 0 0.0 1 2.3 1 2.4 9.5 1.1 34.1

Africa 7 2.8 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Unknown# 12 4.7 0 0.0 1 2.3 0 0.0 N/A

Region

Barwon S W 14 5.5 4 6.7 3 6.8 1 2.4 3.2 1.4 6.3

Grampians 14 5.5 4 6.7 3 6.8 1 2.4 4.9 2.1 9.7

Loddon Mallee 21 8.3 2 3.3 3 6.8 3 7.3 3.6 1.5 7.0

Hume 16 6.3 3 5.0 1 2.3 4 9.8 4.2 1.8 8.3

Gippsland 16 6.3 3 5.0 2 4.5 0 0.0 2.8 0.9 6.5

Western Metro 36 14.2 8 13.3 7 15.9 4 9.8 3.8 2.3 5.9

Northern Metro 42 16.6 8 13.3 9 20.5 16 39.0 5.2 3.6 7.3

Eastern Metro 38 15.0 12 20.0 8 18.2 2 4.9 3.2 2.0 4.9

Southern Metro 51 20.2 14 23.3 8 18.2 8 19.5 3.6 2.4 5.1

Other 5 2.0 2 3.3 0 0.0 2 4.9 7.4 2.0 19.1


Table 5.22.3 Patterns of Birth Defects, Diaphragmatic Hernia, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total

Isolated anomaly* 2 1 6 15 24 58.5Chromosomal 3 1 1 1 6 14.6 Other Same System (CNS) 0 0 0 0 0 0.0 Other Different Systems 0 1 2 8 11 26.8 Total 5 3 9 24 41 100.0

* See p. 7 for the definition of an “isolated” anomaly.

103

5.23 Exomphalos


0.01.02.03.04.05.06.07.08.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Survived > 28 days Liveborn, neonatal deathStillborn Termination< 20 w eeks

Number 23 24 22 17 23 14 22 22 24 31 22 12 N/10,000 3.6 3.6 3.4 2.6 3.5 2.1 3.4 3.5 3.8 5.0 3.5 1.9

Exomphalos British Paediatric Association code 756.70

Herniation of abdominal contents through umbilical insertion and covered by membrane which may or may not remain intact.

• Overall prevalence of exomphalos is not significantly increasing (χ2 for linear trend = 2.3,

p=0.13), and prevalence in 2000 was significantly lower than other years.

• In 19992000, there was a termination of pregnancy in 41.2% of cases.

• Only 30% of cases survive the neonatal period, perhaps because of the strong association (32%) with a chromosomal anomaly (Trisomy 18 in particular).

• There is no significant increased prevalence in one or other sex or in twins.

104

Table 5.23.1 Exomphalos, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 82 37.3 7 15.9 18 32.7 10 29.4 0.9 0.7 1.3

Neonatal death 33 15.0 5 11.4 5 9.1 4 11.8

Stillbirth 59 26.8 9 20.5 6 10.9 6 17.6

Termination < 20 wks 46 20.9 23 52.3 26 47.3 14 41.2

Sex Male 118 53.6 11 25.0 28 50.9 20 58.8 3.0 2.3 3.9

Female 87 39.5 28 63.6 20 36.4 13 38.2 3.3 2.6 4.3


Plurality

Singleton 202 91.8 41 93.2 54 98.2 33 97.1 3.5 2.9 4.2

Twin 17 7.7 3 6.8 1 1.8 0 0.0 3.5 1.0 9.0

Triplet 1 0.5 0 0.0 0 0.0 1 2.9 20.6 0.5 114.8

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • The significantly higher prevalence in older women reflects the association with

chromosomal abnormalities.

• There are no significant associations with maternal country of birth or region of residence.

105

Table 5.23.2 Exomphalos, 1999—2000, by Selected Maternal Characteristics Confinements incluing TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=352)* 220 43 55 34 3.5 3.0 4.2

Maternal Age

<20 12 5.5 1 2.3 2 3.6 1 2.9 3.2 0.9 8.2

20-24 40 18.2 4 9.3 6 10.9 4 11.8 2.7 1.5 4.6

25-29 63 28.6 11 25.6 18 32.7 11 32.4 3.3 2.4 4.5

30-34 61 27.7 11 25.6 12 21.8 11 32.4 2.7 1.9 3.8

35-39 30 13.6 11 25.6 13 23.6 4 11.8 5.2 3.4 7.5

40+ 9 4.1 3 7.0 3 5.5 3 8.8 9.8 4.5 18.6

Unknown# 5 2.3 2 4.7 1 1.8 0 0.0 N/A

Country of Birth

Australia 143 65.0 28 65.1 42 76.4 25 73.5 3.4 2.7 4.2

Oceania inc NZ 2 0.9 2 4.7 1 1.8 3 8.8 6.8 2.5 14.9

UK inc Eire 8 3.6 1 2.3 1 1.8 0 0.0 1.4 0.2 5.1

Europe 11 5.0 5 11.6 1 1.8 1 2.9 4.9 1.9 10.0

Middle East 7 3.2 0 0.0 0 0.0 1 2.9 1.1 0.0 6.2

Asia 16 7.3 4 9.3 8 14.5 2 5.9 4.0 2.2 6.7

Nth America 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Sth America 1 0.5 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Africa 1 0.5 1 2.3 1 1.8 1 2.9 6.2 1.3 18.1

Unknown# 31 14.1 2 4.7 1 1.8 1 2.9 N/A

Region

Barwon S W 11 5.0 2 4.7 7 12.7 4 11.8 5.2 2.7 8.8

Grampians 9 4.1 1 2.3 0 0.0 1 2.9 1.2 0.1 4.4

Loddon Mallee 22 10.0 0 0.0 2 3.6 2 5.9 1.8 0.5 4.6

Hume 14 6.4 1 2.3 2 3.6 5 14.7 4.2 1.8 8.3

Gippsland 17 7.7 0 0.0 2 3.6 3 8.8 2.8 0.9 6.5

Western Metro 23 10.5 3 7.0 11 20.0 6 17.6 4.0 2.4 6.2

Northern Metro 43 19.5 8 18.6 8 14.5 6 17.6 3.5 2.2 5.2

Eastern Metro 43 19.5 11 25.6 8 14.5 4 11.8 3.4 2.1 5.1

Southern Metro 35 15.9 17 39.5 13 23.6 2 5.9 3.8 2.6 5.4

Other 2 0.9 0 0.0 2 3.6 1 2.9 5.6 1.1 16.3


Table 5.23.3 Patterns of Birth Defects, Exomphalos, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total

Isolated anomaly* 4 1 0 7 12 35.3Chromosomal 7 3 1 0 11 32.4 Other Same System (CNS) 3 0 1 0 4 11.8 Other Different Systems 0 2 2 3 7 20.6 Total 14 6 4 10 34 100.0

* See p. 7 for the definition of an “isolated” anomaly.

106

5.24 Gastroschisis


0.0

1.0

2.0

3.0

4.0

5.0

6.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 15 9 6 21 12 7 13 16 23 13 19 20 N/10,000 2.3 1.3 0.9 3.2 1.8 1.1 2.0 2.5 3.7 2.1 3.0 3.2

Gastroschisis British Paediatric Association code 756.71

Visceral herniation through an abdominal wall defect, lateral to an intact umbilical cord.

• There has been a significant increase in the prevalence of this birth defect since 1983 (χ2 for

linear trend = 36.9, p < 0.0001). 1992 prevalence was significantly higher than other years and was at the time when worldwide concern led to investigations of the aetiology of this condition. The association with younger mothers (see below) has been observed in many countries but the cause has not been specifically identified.

• More pregnancy terminations for this condition occurred in 19992000 than previously reported.

• A small proportion is stillborn (5%) and another 3% die in the neonatal period. This condition is not often associated with another birth defect, being isolated in 74% of cases and surviving beyond 28 days in 79.5% of cases.

107

Table 5.24.1 Gastroschisis, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 77 77.0 21 72.4 29 80.6 31 79.5 2.2 1.7 2.7

Neonatal death 6 6.0 0 0.0 1 2.8 1 2.6

Stillbirth 6 6.0 5 17.2 4 11.1 2 5.1

Termination < 20 wks 11 11.0 3 10.3 2 5.6 5 12.8

Sex Male 54 54.0 17 58.6 18 50.0 20 51.3 2.8 2.2 3.7

Female 39 39.0 11 37.9 17 47.2 16 41.0 2.4 1.7 3.2


Plurality

Singleton 98 98.0 28 96.6 36 100.0 35 89.7 2.7 2.2 3.3

Twin 2 2.0 1 3.4 0 0.0 3 7.7 3.5 1.0 9.0

Triplet 0 0.0 0 0.0 0 0.0 1 2.6 20.6 0.5 114.8

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • There is a highly significant inverse association with maternal age, with a significant

increased prevalence in teenage mothers. A number of international studies are underway to examine this unusually high risk. There have been no cases born to women more than 39 years of age since 1983.

• There are no significant maternal country of birth or regional associations.

108

Table 5.24.2 Gastroschisis, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=204)* 100 29 36 39 2.8 2.3 3.4

Maternal Age

<20 16 16.0 5 17.2 12 33.3 8 20.5 20.0 12.9 29.6

20-24 33 33.0 12 41.4 12 33.3 14 35.9 7.4 5.2 10.1

25-29 28 28.0 6 20.7 10 27.8 9 23.1 2.1 1.3 3.1

30-34 20 20.0 4 13.8 2 5.6 5 12.8 0.9 0.4 1.6

35-39 2 2.0 2 6.9 0 0.0 3 7.7 0.9 0.3 2.1

40+ 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Unknown# 1 1.0 0 0.0 0 0.0 0 0.0 N/A

Country of Birth

Australia 75 75.0 21 72.4 31 86.1 33 84.6 3.0 2.4 3.8

Oceania inc NZ 2 2.0 1 3.4 0 0.0 1 2.6 2.3 0.3 8.2

UK inc Eire 4 4.0 3 10.3 2 5.6 3 7.7 5.7 2.4 11.1

Europe 3 3.0 0 0.0 0 0.0 1 2.6 0.7 0.0 3.9

Middle East 0 0.0 1 3.4 1 2.8 1 2.6 3.3 0.7 9.7

Asia 3 3.0 2 6.9 1 2.8 0 0.0 0.9 0.2 2.5

Nth America 1 1.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Sth America 1 1.0 1 3.4 0 0.0 0 0.0 4.7 0.1 26.3

Africa 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Unknown# 11 11.0 0 0.0 1 2.8 0 0.0 N/A

Region

Barwon S W 5 5.0 6 20.7 3 8.3 2 5.1 4.4 2.2 7.8

Grampians 4 4.0 3 10.3 2 5.6 3 7.7 4.9 2.1 9.7

Loddon Mallee 4 4.0 4 13.8 0 0.0 5 12.8 4.0 1.8 7.6

Hume 7 7.0 2 6.9 3 8.3 4 10.3 4.7 2.2 9.0

Gippsland 5 5.0 0 0.0 4 11.1 3 7.7 3.9 1.6 8.0

Western Metro 17 17.0 2 6.9 3 8.3 3 7.7 1.6 0.7 3.2

Northern Metro 16 16.0 2 6.9 6 16.7 7 17.9 2.4 1.3 3.9

Eastern Metro 15 15.0 6 20.7 6 16.7 1 2.6 1.9 1.0 3.3

Southern Metro 25 25.0 4 13.8 9 25.0 8 20.5 2.5 1.5 3.8

Other 2 2.0 0 0.0 0 0.0 3 7.7 5.6 1.1 16.3


Table 5.24.3 Patterns of Birth Defects, Gastroschisis, 1999—2000

Type TOP < 20 Weeks


Surviving > 28 Days

Total % of Total


109

5.25 Trisomy 21


6.0

11.0

16.0

21.0

26.0

31.0

83-85

86-88

89-91

1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

-10

10

30

50

70

90

110

130

150

170

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 103 112 110 113 112 126 138 107 146 134 166 156 N/10,000 16.0 16.7 16.8 17.0 17.2 19.3 21.6 16.9 23.3 21.5 26.4 24.8

Trisomy 21 British Paediatric Association code 758.00 - 758.09

Down syndrome - additional chromosome 21.

• This is the most common of the autosomal aneuploidies with an overall prevalence in 2000 of

24.8/10,000 or 1 in 400 pregnancies.

• The number of reported trisomy 21 pregnancies (terminations plus births) has significantly increased since 1983 (χ2 for linear trend = 91.8, p<0.0001) .

• There has been an increase in the number of terminations of pregnancy but no major decline in the number of actual livebirths.

110

Table 3.25.1 Trisomy 21, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 857 72.0 123 50.2 108 38.6 115 35.7 9.3 8.4 10.3

Neonatal death 42 3.5 5 2.0 8 2.9 9 2.8

Stillbirth 52 4.4 12 4.9 16 5.7 17 5.3

Termination < 20 wks 239 20.1 105 42.9 148 52.9 181 56.2

Sex Male 660 55.5 125 51.0 140 50.0 167 51.9 22.2 20.1 24.3

Female 508 42.7 98 40.0 103 36.8 109 33.9 16.9 15.1 18.9


Plurality

Singleton 1,151 96.7 240 98.0 272 97.1 316 98.1 22.6 21.1 24.2

Twin 36 3.0 4 1.6 8 2.9 5 1.6 14.9 8.7 23.9

Triplet 3 0.3 1 0.4 0 0.0 1 0.3 41.2 5.0 148.9


• There is a significant excess of males with Down syndrome.

• There is no association with twinning.

• The expected significant association with maternal age is seen. From 19831994, 62% of the babies with trisomy 21 were born to women who were less than 35 years of age, but in 19992000, only 42% were identified in women less than 35 years. This shift in proportion and the overall increase in prevalence is due to a number of reasons:

- the increasing number of older women having babies

- less older women having prenatal diagnosis and

- detection in early pregnancy, using ultrasound and maternal serum screening, of affected fetuses, that would once have spontaneously aborted and never entered the statistics.

• The overall prevalence for women 35-39 years is approximately 1 in 190 and for women 40 years and over it is 1 in 50.

• There is no significant association with mother’s country of birth

• Women living in two of the rural regions (Grampians and Loddon Mallee) have significantly lower prevalence than each of the Metropolitan regions, a factor probably related to the age distribution of the populations. (Refer to Table 2.6 in Births in Victoria, 1999—2000 p.20 (9)).

A full account of all Prenatal Diagnosis done in Victoria is available from the Perinatal Data Collection Unit as a separate report, and on the website.

111

Table 5.25.2 Trisomy 21, 1999—2000, by Selected Maternal Characteristics Confinements including TOPs

(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=2,030)* 1,183 245 280 322 22.8 21.2 24.3

Maternal Age

<20 24 2.0 4 1.6 1 0.4 2 0.6 5.6 2.2 11.5

20-24 117 9.9 15 6.1 14 5.0 6 1.9 6.8 4.7 9.5

25-29 249 21.0 28 11.4 33 11.8 44 13.7 8.7 7.2 10.6

30-34 326 27.6 65 26.5 63 22.5 84 26.1 17.1 14.9 19.6

35-39 306 25.9 82 33.5 97 34.6 105 32.6 52.3 46.5 58.9

40+ 130 11.0 47 19.2 61 21.8 75 23.3 198.6 171.4 230.1

Unknown# 31 2.6 4 1.6 11 3.9 6 1.9 N/A

Country of Birth

Australia 737 62.3 170 69.4 182 65.0 206 64.9 19.9 18.2 21.5

Oceania inc NZ 18 1.5 6 2.4 6 2.1 4 1.2 18.2 10.4 29.5

UK inc Eire 47 4.0 13 5.3 10 3.6 12 3.7 24.8 17.3 34.4

Europe 80 6.8 14 5.7 11 3.9 9 2.8 23.6 16.4 33.0

Middle East 20 1.7 3 1.2 10 3.6 4 1.2 18.8 10.9 30.0

Asia 76 6.4 19 7.8 19 6.8 28 8.7 18.9 14.7 24.2

Nth America 5 0.4 1 0.4 2 0.7 1 0.3 20.5 5.6 52.6

Sth America 7 0.6 1 0.4 0 0.0 3 0.9 18.9 5.1 48.4

Africa 14 1.2 4 1.6 1 0.4 4 1.2 18.6 8.5 35.4

Unknown# 179 15.1 14 5.7 39 13.9 51 15.8 N/A

Region

Barwon S W 74 6.3 14 5.7 13 4.6 17 5.3 17.5 12.7 23.5

Grampians 49 4.1 3 1.2 8 2.9 11 3.4 13.5 8.5 20.4

Loddon Mallee 77 6.5 11 4.5 7 2.5 14 4.3 13.4 9.8 20.2

Hume 60 5.1 14 5.7 15 5.4 15 4.7 23.1 16.7 31.0

Gippsland 62 5.2 8 3.3 9 3.2 15 4.7 17.8 12.2 25.1

Western Metro 147 12.4 28 11.4 33 11.8 44 13.7 21.0 17.3 25.5

Northern Metro 212 17.9 48 19.6 71 25.4 49 15.2 26.4 22.6 30.8

Eastern Metro 234 19.8 51 20.8 55 19.6 64 19.9 25.0 21.5 29.1

Southern Metro 243 20.5 63 25.7 59 21.1 87 27.0 24.7 21.5 28.5

Other 13 1.1 4 1.6 9 3.2 6 1.9 35.3 21.3 55.1


112

5.26 Trisomy 13

Figure 5.26 Prevalence and, Number of Cases by Year

0.0

1.0

2.0

3.0

4.0

5.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

2

4

6

8

10

12

14

16

18

20

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Termination< 20 w eeks

Stillborn

Liveborn, neonatal death

Survived > 28 days

Number 7 8 13 9 19 10 15 17 18 13 18 18 N/10,000 1.1 1.2 2.0 1.4 2.9 1.5 2.3 2.7 2.9 2.1 2.9 2.9


Patau syndrome - additional chromosome 13

• This more uncommon autosomal trisomy has an overall prevalence of 2.9/ 10,000 in

19992000. As with trisomy 21, there has been a significant increase in prevalence in the last four years, compared to 19831994, due to an increase in the number of fetuses detected in utero and pregnancies terminated. (χ2 for linear trend = 24.32, p<0.0001).

• No babies with this condition survived the neonatal period in 19992000 and there were no stillbirths in 2000.

• There is no significant difference in male and female prevalence, and no increased prevalence in twins.

113

Table 5.26.1 Trisomy 13, 19992000, by Selected Infant Characteristics All Births including TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 11 10.2 2 6.3 2 6.5 1 2.8 0.1 0.0 0.3

Neonatal death 42 38.9 4 12.5 5 16.1 5 13.9

Stillbirth 18 16.7 7 21.9 5 16.1 3 8.3

Termination < 20 wks 37 34.3 19 59.4 19 61.3 27 75.0

Sex Male 55 50.9 9 28.1 15 48.4 18 50.0 2.2 1.6 2.9

Female 47 43.5 19 59.4 12 38.7 16 44.4 2.6 1.9 3.4


Plurality

Singleton 106 98.1 30 93.8 30 96.8 35 97.2 2.6 2.1 3.2

Twin 2 1.9 1 3.1 1 3.2 1 2.8 2.6 0.5 7.7

Triplet 0 0.0 1 3.1 0 0.0 0 0.0 20.6 0.5 114.8

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • There is the expected trend with advancing maternal age. Women 35 years and older have a

significantly increased risk of having a baby with this condition compared with women less than 35 years. For women 40 years and older, the risk of having a baby with this condition is almost the same as that for a 30-34 year old woman having a baby with trisomy 21.

• Unlike trisomy 21, younger women have the highest proportion of babies with this birth defect with 67% born to women less than 35 years

• There are no associations with mother’s country of birth or region of residence.

114


(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=207)* 108 32 31 36 2.7 2.2 3.3

Maternal Age

<20 2 1.9 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

20-24 17 15.7 1 3.1 3 9.7 2 5.6 1.2 0.4 2.5

25-29 27 25.0 7 21.9 5 16.1 9 25.0 1.7 1.1 2.7

30-34 28 25.9 4 12.5 5 16.1 13 36.1 1.8 1.1 2.7

35-39 20 18.5 12 37.5 9 29.0 6 16.7 5.0 3.3 7.3

40+ 10 9.3 7 21.9 7 22.6 3 8.3 18.4 10.8 29.5

Unknown# 4 3.7 1 3.1 2 6.5 3 8.3 N/A

Country of Birth

Australia 61 56.5 20 62.5 18 58.1 20 55.6 2.1 1.6 2.7

Oceania inc NZ 2 1.9 0 0.0 1 3.2 1 2.8 2.3 0.3 8.2

UK inc Eire 2 1.9 2 6.3 4 12.9 1 2.8 5.0 2.0 10.2

Europe 6 5.6 4 12.5 1 3.2 1 2.8 4.2 1.5 9.1

Middle East 3 2.8 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Asia 8 7.4 2 6.3 0 0.0 2 5.6 1.1 0.3 2.9

Nth America 1 0.9 1 3.1 1 3.2 0 0.0 10.3 1.2 37.1

Sth America 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Africa 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Unknown# 25 23.1 3 9.4 6 19.4 11 30.6 N/A

Region

Barwon S W 7 6.5 4 12.5 3 9.7 1 2.8 3.2 1.4 6.3

Grampians 7 6.5 0 0.0 1 3.2 3 8.3 2.5 0.7 6.3

Loddon Mallee 6 5.6 1 3.1 0 0.0 0 0.0 0.4 0.0 2.5

Hume 2 1.9 3 9.4 2 6.5 1 2.8 3.1 1.2 6.9

Gippsland 4 3.7 0 0.0 1 3.2 2 5.6 1.7 0.3 4.9

Western Metro 8 7.4 3 9.4 5 16.1 5 13.9 2.6 1.4 4.4

Northern Metro 20 18.5 7 21.9 4 12.9 7 19.4 2.8 1.7 4.5

Eastern Metro 25 23.1 4 12.5 8 25.8 5 13.9 2.5 1.5 4.0

Southern Metro 29 26.9 10 31.3 6 19.4 12 33.3 3.3 2.2 4.8

Other 0 0.0 0 0.0 1 3.2 0 0.0 1.9 0.0 10.4


115

5.27 Trisomy 18


0.0

2.0

4.0

6.0

8.0

10.0

83-85 86-88 89-91 1992 1993 1994 1995 1996 1997 1998 1999 2000

n/10

,000

0

5

10

15

20

25

30

35

40

45

50

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000


Number 24 24 38 23 27 37 32 48 32 44 42 36 N/10,000 3.7 3.6 5.8 3.5 4.2 5.7 5.0 7.6 5.1 7.1 6.7 5.7


Edward syndrome - additional chromosome 18.

• This trisomy is more than twice as common as trisomy 13 with overall prevalence from 1995 2000 of 6.2/10,000. The prevalence in the last two years has not increased, but there has been a significant increase since 1983 (χ2 for linear trend = 56.5, p<0.0001). Most of the increase is in the number of recognised affected pregnancies and subsequent termination.

• 13% of cases or 10 babies survived the neonatal period in 19992000, which is a higher figure than previously reported.

• There is a non-significant excess of females and very few twins recorded with this condition.

116

Table 5.27.1 Trisomy 18, 19992000, by Selected Infant Characteristics All Births plus TOPs (83-94) (95-96) (97-98) (99-00) Rate/

10,000 (95-00)

95% Confidence


Survived > 28 days 33 12.6 4 5.0 5 6.6 10 12.8 0.5 0.3 0.8

Neonatal death 72 27.5 15 18.8 8 10.5 7 9.0

Stillbirth 61 23.3 17 21.3 16 21.1 14 17.9

Termination < 20 wks 96 36.6 44 55.0 47 61.8 47 60.3

Sex Male 117 44.7 27 33.8 34 44.7 28 35.9 4.6 3.7 5.7

Female 133 50.8 44 55.0 30 39.5 44 56.4 6.4 5.4 7.7


Plurality

Singleton 256 97.7 79 98.8 76 100.0 77 98.7 6.3 5.6 7.2

Twin 6 2.3 1 1.3 0 0.0 1 1.3 1.8 0.2 6.3

Triplet 0 0.0 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Other 0 0.0 0 0.0 0 0.0 0 0.0 0.0 *See Appendix D for denominator figures #95% of unknowns were in terminations before 20 weeks • As with the other Trisomies, overall prevalence increased markedly with increasing maternal

age. Women 40 years and older have a slightly lower risk of having a baby with Trisomy 18 compared with the risk of a 35-36 year old women having a baby with Trisomy 21.

• In 19992000, the majority (56.4%) of cases were found in women 35 year and over compared with earlier years when more were found in younger women. This shift in proportion was also seen for Trisomy 21 and is due to the same reasons (listed on p.110)

• Asian-born women have a significantly increased risk of having a baby with this condition compared to Australian-born women.

• There are no significant associations with region of residence.

117


(83-94) (95-96) (97-98) (99-00) Rate/ 10,000 (95-00)

95% Confidence

Interval


Total (n=496) 262 80 76 78 6.3 5.5 7.2

Maternal Age

<20 4 1.5 0 0.0 2 2.6 0 0.0 1.6 0.2 5.8

20-24 23 8.8 3 3.8 3 3.9 5 6.4 2.1 1.1 3.8

25-29 58 22.1 13 16.3 8 10.5 13 16.7 2.8 2.0 4.0

30-34 60 22.9 22 27.5 14 18.4 15 19.2 4.1 3.1 5.4

35-39 56 21.4 24 33.8 29 38.2 21 26.9 14.2 11.3 17.8

40+ 50 19.1 18 22.5 18 23.7 23 29.5 64.0 49.2 83.1

Unknown# 11 4.2 0 0.0 2 2.6 1 1.3 N/A

Country of Birth

Australia 127 48.5 45 56.3 43 56.6 44 56.4 4.7 3.9 5.6

Oceania inc NZ 5 1.9 2 2.5 1 1.3 3 3.8 6.8 2.5 14.9

UK inc Eire 14 5.3 5 6.3 3 3.9 3 3.8 7.8 3.9 13.9

Europe 9 3.4 5 6.3 3 3.9 2 2.6 6.9 3.3 12.8

Middle East 4 1.5 0 0.0 1 1.3 3 3.8 4.4 1.2 11.3

Asia 23 8.8 17 21.3 14 18.4 9 11.5 11.5 8.2 15.6

Nth America 1 0.4 1 1.3 0 0.0 1 1.3 10.3 1.2 37.1

Sth America 3 1.1 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Africa 4 1.5 0 0.0 0 0.0 0 0.0 0.0 0.0 0.0

Unknown# 72 27.5 5 6.3 11 14.5 13 16.7 N/A

Region

Barwon S W 12 4.6 5 6.3 6 7.9 6 7.7 6.8 3.9 10.8

Grampians 8 3.1 3 3.8 2 2.6 0 0.0 3.1 1.0 7.2

Loddon Mallee 10 3.8 4 5.0 2 2.6 2 2.6 3.6 1.5 7.0

Hume 11 4.2 1 1.3 3 3.9 8 10.3 6.3 3.3 11.0

Gippsland 11 4.2 1 1.3 7 9.2 4 5.1 6.7 3.4 11.7

Western Metro 34 13.0 11 13.8 8 10.5 14 17.9 6.6 4.5 9.3

Northern Metro 43 16.4 12 15.0 10 13.2 17 21.8 6.1 4.4 8.4

Eastern Metro 73 27.9 18 22.5 14 18.4 13 16.7 6.6 4.8 8.9

Southern Metro 57 21.8 24 30.0 22 28.9 12 15.4 6.9 5.3 9.0

Other 3 1.1 1 1.3 2 2.6 2 2.6 9.3 3.0 21.7

Unknown 0 0.0 0 0.0 0 0.0 0 0.0 N/A

#95% of unknowns were in terminations before 20 weeks

119

References

1. The Consultative Council on Obstetric and Paediatric Mortality and Morbidity (2001), Annual Report for the Year 1999, incorporating the 38th Survey of Perinatal Deaths, Melbourne.

2. Riley M & Halliday J (2000), Birth Defects in Victoria 19832000, Perinatal Data Collection Unit, Victorian Government Department of Human Services, 2000.

3. Lumley J., Palma S., Fischer M., Robertson H.(1988), ‘The tip of the iceberg: A validation study of the Victorian Congenital Malformations/Birth Defects Register’, Australian Paediatric Journal, no. 24: p.244-6

4. Kilkenny M., Riley M., Lumley J. (1995), ‘Follow-up validation study study of the Victorian Congenital Malformations Register’, Journal of Paediatric & Child Health, no. 31 p.323-5.

5. Riley M, Howard J, Dale K, Palma S, Halliday J (2001), Validating notifications of pregnancy terminations for birth defects before 20 weeks gestation, Health Information Management, 30 No.2

6. Riley M. & Halliday J (1996), Congenital Malformations in Victoria 1983-1994, Perinatal Data Collection Unit, Victorian Government Department of Human Services, Melbourne.

7. Hurst T, Shafir E, Day P & Lancaster P. 1999, Congenital Malformations Australia 1995 and 1996, AIHW Cat. No. PER 8, Sydney: Australian Institute of Health and Welfare National Perinatal Statistics Unit (Birth Defects Series No.3)

8. Koori Health Counts: How many Koori babies were born in Victoria in 1999 (1999), Koori Health Unit, Public Health Division, Victorian Government Department of Human Services, No.2

9. Riley M & Halliday J (2001), Births in Victoria 19992000, Perinatal Data Collection Unit, Victorian Government of Human Services, Melbourne, 2001

120

Appendix A: Publications, January 1999 – July 2002 1999

Hoy J, Venn A, Halliday J, Kovacs G, Waalwyk K (1999), Perinatal and obstetric outcomes of donor inseminations using crypopreserved semen in Victoria, Australia, Human Reproduction, 14, 7: 1760-1764

Watson M, Watson L, Bell R, Halliday J, Burford N, Brennecke S (1999), A randomised community intervention trial to increase awareness and knowledge of the role of periconceptional folate in women of child bearing age, Health Expectations, 2: 255-265

Sowter B, Doyle L, Morley C, Altmann A, Halliday J (1999), Is sudden infant death syndrome still more common in very low birth weight infants in the 1990s? Med J Aus, 171: 411-413

2000

Vagg L, Taylor O, Riley M, Palma S, Halliday J (1999/2000), Validation of the Victorian Perinatal Morbidity Statistics form: new items, pre-coded text and free text. Health Info Management, 29, 3: 118-122

Owen TJ., Halliday JL., Stone CA., (January 2000), Neural tube defects in Victoria, Australia: potential contributing factors and public health implication. AusNZ J Pub Health, 24 :584-589

Halliday JL., Riley M (September 2000), Fortification of Foods with Folic Acid, New Engl J Med, 343, 13: 970-971.

Stone C, Halliday J, Lumley J, Brennecke S (October 2000) Vaginal births after Caesarean (VBAC), Paed Peri Epidem 14, 4: 340-348

Halliday J, Reddihough D, Byron K, Ekert H, Ditchfield M. Hemiplegic cerebral palsy and the factor V Leiden mutation. J Med Genet 37: 787-789 (2000)

Doyle L, Morley C, Halliday J. Prediction of survival for preterm births. Br Med J 320: 647 (2000)

2001

Ward B., Lambert S., Halliday J. (March 2001), Congenital Rubella Syndrome Surveillance -Can we do better?, Victorian Infectious Diseases Bulletin

Connelly JF, Coakley JC, Gold H, Francis I, Mathur KS, Rickards AL, Price GJ, Halliday JL, Wolfe R (June 2001) Newborn screening for congenital hypothyroidism, Victoria, Australia. Paper 1 – the screening programme, demography, baseline demographic data and diagnostic classification, Pediatric Endocrinology and Metabolism

Watson M, Watson L, Bell R, Halliday J (2001). The increasing knowledge of the role of periconceptional folate in Victorian women of child-bearing age: Follow-up of a randomised community intervention trial. AusNZ J Pub Health , 25:389-395.

Riley M, Howard J, Dale K, Palma S, Halliday (2001), Validating notifications of pregnancy terminations for birth defects before 20 weeks gestation, Health Information Management, 30 No.2

January – July 2002 Nisbet D, Robinson H, Halliday J, de Crespigny L. Letter response to Ultrasoninc fetal measurements: new Australian standards for the new millenium. Aust NZ J Obstet Gynaecol, 101-102 (2002)

Watson L, Watson M, Halliday J, Bell R. Consequences of Surveying Folate Awareness. Health Expectations 5, 1: 38-46 (2002)

Stone C, Halliday J, Wein P, McLachlan KA, Tippett C. Incidence and risk factors for gestational diabetes in Victorian women in 1996, (accepted Med J Aus, June 2002)

121

Collins V, Halliday J, Williamson R, What predicts the use of genetic counseling services after the birth of a child with Down Syndrome (Accepted J Genetic Couns, May 2002)

Vallino-Napoli LD, Riley MM, Halliday J, An Epidemiological Study of Isolated Cleft Lip and/or Palate in Victoria, Australia from 1983-2000 (submitted Cleft Palate-Craniofacial Journal, May 2002)

Phyland S, Taylor O, Palma S, Riley M, Halliday J, Validation of the Victorian Birth Defects Register, (to be submitted 2002)

Smithers P, Halliday J, Hale, L, Talbot M, Breheny S, Healy D. Mixed sex twins: IVF compared with non-IVF. (submitted Fert and Stert, Aug 2002)

Amniocentesis and Chorion Villus Sampling

There has been continued monitoring of prenatal diagnosis by the Murdoch Childrens Research Institute (MCRI) in collaboration with Perinatal Data Collection Unit. An annual report is produced which is available from the Public Health and Genetics Unit of the MCRI (Tel: 83416260).

Webley C & Halliday J (Oct 2001) Annual Report on Prenatal Diagnosis in Victoria 2000

Webley C & Halliday J (Aug 2002) Annual Report on Prenatal Diagnosis in Victoria 2001

Halliday J, Warren R, MacDonald G, Rice P, Bell R, Watson L (2001) Prenatal diagnosis for women 37 years and over: to have or not to have Prenatal Diagnosis 21: 842-847

Liamputtong P, Halliday J, McDonald G, Warren R, Watson L, Bell R. Why do women decline prenatal screening and diagnosis? Australian women’s perspective. (accepted Women and Health, July 2001)

122

Appendix B: List of Exclusions NB: There has been some variation in this list of exclusions between 1983-2000. Some excluded conditions may be included in this report if they were previously not excluded AND occur with other birth defect.

Abnormal palmar creases

Accessory nipples

Anal fissure

Balanced autosomal translocation (unless ocurring with structural defects)

Birth injuries

Birth marks (smaller than 4cm, not including giant naevus)

Bowing of legs (unless severe)

Blocked tear ducts (dacrostenosis)

Brushfield spots

Cephalhaematoma

Cleft gum

Clicky hips

Clinodactyly

Craniotabes (unless severe)

Dermatogplyphic abnormalities

Ear abnormalities (minor)

Epicanthic folds

Gastro-oesophageal reflux

Haemangioma (<4 cm wide)

Hernia - inguinal, umbilical

High-arched palate

Hydrocele

Hypertelorism

Imperforate hymen

Laryngeal stridor

Larygomalacia

Low slung/set ears

Macroglossia (large tongue)

Meckel’s diverticulum

Meconium ileus

Mental retardations (unless occurring with a syndrome/structural defect)

Metatarsus varus

Micrognathia (unless severe)

Mongolian spots

Occiput, flat/prominent

Patent ductus arteriosus (< 37 weeks)

Philtrum, long/short

Plagiocephaly

123

Pre-auricular sinus

Prominent forehead

Protruding tongue

Ptosis

Pyloris stenosis

Retrognathia (unless severe)

Rocker-bottom feet (prominent heels)

Sacral pits, dimples, sinuses

Short sternum

Simian creases

Single umbilical artery/2 vessels in cord

Skin folds/tags

Slanting eyes

Small mouth

Spina bifida occulta

Sternomastoid tumour

Subluxating knee joint

Talipes (positional)

Toe anomalies - minor

Tongue tie

Torticollis

Ureteric reflux (ultrasound diagnosed)

Webbing of 2nd & 3rd toes/fingers

Wide suture lines

124

Appendix C: Routine Data Items Contained in the Birth Defects/Congenital Malformations Register

Maternal data: postcode, date of birth, method of prenatal diagnosis, name

Infant /fetus data: hospital of birth, date of birth (or termination), sex, birthweight, plurality,

rank, discharge status, date of death (if applicable), BPA Codes for congenital

malformations, position code, source of notification

Other data items available from linkage to the Perinatal Morbidity Statistics Form:

(I) Maternal items: UR number, local government area, region, country of birth, aboriginality,

discharge date and status, marital status, number of previous pregnancies,

date of completion of last pregnancy, outcome of last pregnancy, maternal

medical conditions, obstetric complications, indication(s) for operative

delivery, complications of labour birth and postnatal, procedures and

operations, type of labour, presentation, method of delivery

(2) infant data items: apgar, time to establish respiration, resuscitation methods, neonatal

morbidity

125

Appendix D: Denominator Figures for Infant and Maternal Characteristics for Twenty Seven Selected Defects

Appendix D.1 Denominator Statistics for Maternal Age, by Confinements, for Twenty Seven Selected Defects, 19952000

Maternal Age Group Number Per Cent

< 20 12,505 3.3

20-24 51,442 13.8

25-29 120,207 32.3

30-34 124,247 33.4

35-39 54,286 14.6

40+ 9,218 2.5

Unknown 81 0.0

Total 371,986 100.0

Appendix D.2 Denominator Statistics for Maternal Country of Birth, by Confinements, for Twenty Seven Selected Defects, 19952000

Country of Birth Number Per Cent

Australia 280,924 75.5

Oceania inc NZ 8,790 2.4

UK inc Eire 14,139 3.8

Middle East 14,410 3.9

Asia 34,886 9.4

Nth America 1,948 0.5

Sth America 2,116 0.6

Africa 4,830 1.3

Unknown 888 0.2

Total 371,986 100.0

Appendix D.3 Denominator Statistics for Humans Services Region of Residence, by Confinements, for Twenty Seven Selected Defects, 19952000

Region Number Per Cent

Barwon SW 25,181 6.8

Grampians 16,266 4.4

Loddon Mallee 22,377 6.0

Hume 19,077 5.1

Gippsland 17,992 4.8

Western Metro 50,005 13.4

Northern Metro 63,575 17.1

Eastern Metro 67,986 18.3

Southern Metro 84,145 22.6

Other 5,375 1.4

Unknown 7 0

Total 371,986 100.0

126

Appendix D.4 Denominator Statistics for Baby’s Outcome, All Pregnancies, for Twenty Seven Selected Defects, 19952000

Outcome Number Per Cent

Survived > 28 days 372,370 98.5

Neonatal Death 1,281 0.3

Stillbirth 2,669 0.7

Termination < 20 weeks 1,681 0.4

Total 378,001 100.0

Appendix D.5 Denominator Statistics for Sex, All Pregnancies, for Twenty Seven Selected Defects, 19952000

Sex Number Per Cent

Male 194,266 51.4

Female 183,188 48.5

Indeterminate 94 0.0

Unknown 453 0.0

Total 378,001 100.0

Appendix D.6 Denominator Statistics for Plurality, All Pregnancies, for Twenty Seven Selected Defects, 19952000

Plurality Number Per Cent

Singleton 366,109 96.9

Twin 11,386 3.0

Triplet 485 0.1

Quad 16 0.0

Unknown 5 0.0

Total 378,001 100.0

127

Appendix E: Department of Human Services - Rural Regions

128

Appendix E: Department of Human Services - Metropolitan Regions

129

Appendix F: Allocation of Postcodes to Current (1998) LGA Boundaries Barwon South West

3211, 3212, 3214 to 3228, 3230, 3232,3233,3235 to 3243, 3249 to 3251, 3253, 3254, 3256, 3257, 3260, 3264 to 3282, 3284 to 3287, 3289, 3290, 3292 to 3294, 3300 to 3306, 3309 to 3312, 3314, 3315, 3323 to 3325, 3361, 3407, 3408, 3410

Grampians

3231, 3291, 3317 to 3319, 3321, 3322, 3328 to 3334, 3340 to 3343, 3345, 3350 to 3353, 3355 to 3357, 3360, 3363, 3364, 3370, 3371, 3373, 3375, 3377 to 3381, 3384 to 3401, 3405, 3409, 3412 to 3415, 3417 to 3420, 3422 to 3424, 3458 to 3461, 3467 to 3469, 3478, 3485, 3487 to 3489, 3491

Loddon Mallee

3430 to 3451, 3453, 3462 to 3465, 3472, 3475, 3480, 3482, 3483, 3490, 3494, 3496, 3498, 3500 to 3502, 3505 to 3507, 3509, 3512, 3515 to 3518, 3520, 3523, 3525, 3527, 3529 to 3537, 3539, 3540, 3542, 3544, 3546, 3549 to 3551, 3555 to 3576, 3578 to 3591, 3594 to 3601, 3612, 3620 to 3625, 3654

Hume

3521, 3522, 3603, 3604, 3606 to 3611, 3613 to 3618, 3627 to 3641, 3644 to 3649, 3651 to 3653, 3655, 3656, 3658 to 3678, 3682 to 3691, 3693 to 3701, 3704 to 3749, 3756, 3758, 3762 to 3764, 3778, 3779

Gippsland

3816 to 3825, 3828, 3831 to 3842, 3844, 3847, 3850 to 3904, 3909, 3921 to 3925, 3945, 3946, 3950 to 3968, 3971, 3979, 3984, 3987 to 3996

Western Metro

3000 to 3003, 3006, 3011 to 3042, 3051 to 3053, 3335 to 3338, 3427

Northern Metro

3043 to 3049, 3054 to 3099, 3121, 3428 to 3430, 3750 to 3754, 3757, 3759 to 3761

Eastern Metro

3101 to 3140, 3146 to 3160, 3166, 3168, 3170, 3178 to 3180, 3755, 3765 to 3767, 3770, 3775, 3777, 3782, 3785 to 3799

Southern Metro

3004, 3141 to 3146, 3148, 3161 to 3165, 3167, 3169, 3171 to 3177, 3181 to 3207, 3781 to 3783, 3802 to 3815, 3910 to 3920, 3926 to 3944, 3975 to 3978, 3980, 3981

Other

Postcodes outside Victoria

birth defects in victoria 1999—2000/media/health/files...5.25 trisomy 21 109 5.26 trisomy 13 112...

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