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The Journal of Maternal-Fetal & Neonatal Medicine
ISSN: 1476-7058 (Print) 1476-4954 (Online) Journal homepage: http://www.tandfonline.com/loi/ijmf20
Influence of mode of delivery on outcomes inpreterm breech infants presenting in labor
Claire O’Reilly, Mark P. Hehir & Rhona Mahony
To cite this article: Claire O’Reilly, Mark P. Hehir & Rhona Mahony (2018): Influence of mode ofdelivery on outcomes in preterm breech infants presenting in labor, The Journal of Maternal-Fetal &Neonatal Medicine, DOI: 10.1080/14767058.2018.1500542
To link to this article: https://doi.org/10.1080/14767058.2018.1500542
Accepted author version posted online: 12Jul 2018.
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INFLUENCE OF MODE OF DELIVERY ON OUTCOMES IN
PRETERM BREECH INFANTS PRESENTING IN LABOR
Claire O’REILLY1 MB BCh, Mark P HEHIR1 MD MBA, Rhona MAHONY1 MD
FRCOG
Institutions:
1National Maternity Hospital,
Holles St,
Dublin 2.
Author for correspondence:
Dr Mark P Hehir MD MBA BSc MRCPI MRCOG
E-mail: [email protected]
Tel +353 1 6373100
FINANCIAL DISCLOSURE: The authors report no conflict of interest.
Word Count: Abstract = 191
Text = 2499
Funding: No funding was received for this work.
Short Title: Delivery and outcomes of preterm breech infants
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Precis: Vaginal delivery of preterm breech infants decreases after 27 weeks gestation,
however it remains an important aspect of contemporary practice and a necessary skill for
clinicians.
Abstract
Objective: Rates of vaginal breech delivery at term have fallen significantly. We sought to
examine rates of preterm vaginal breech delivery and outcomes associated with delivery
route.
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Methods:This retrospective cohort study was carried out at a large tertiary referral centre
serving an urban population, from 2001-2011. The primary objective was to compare
outcomes of breech presenting preterm infants according to mode of delivery. The
incidence of preterm breech delivery was examined as well as maternal and neonatal
outcomes associated with vaginal and abdominal delivery of preterm breech infants.
Results:A total of 15% (413/2759) of breech presenting infants delivered prior to 37 weeks
gestation. In extreme prematurity (<28 weeks) the majority (88%; 37/42) of those who
presented in labor delivered vaginally, this rate fell to 47% (63/134) after 28 weeks. Infants
delivered vaginally after 28 weeks were more likely to have an Apgar <7 at 5mins, than
those who had a cesarean delivery (22.5% [16/71] vs. 9% [25/278], p=0.002; NNT=4).
Maternal blood loss >500ml was more likely in those patients delivered by cesarean section
(24.2% [74/305] vs. 3.7% [4/108]; p<0.0001; NNT=2).
Conclusion:These results demonstrate that vaginal delivery of a preterm breech –
presenting infant is a necessary skill for all birth attendants in contemporary practice,
particularly prior to 28 weeks gestation.
INTRODUCTION
Breech presentation occurs in 3-4% of all deliveries1 and is associated with an increased
risk of neonatal morbidity and mortality compared with the overall obstetric population.2
The appropriate mode of delivery of a breech presentation was investigated by the Term
Breech Trial (TBT), which recommended elective cesarean delivery of breech infants
at term.3 Published data from our institution has shown that cesarean delivery of breech
infants has become standard practice in contemporary obstetrics, with vaginal breech
delivery now a relatively rare event.4 This practice carries the potential to cost practicing
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clinicians experience in vaginal breech delivery. The TBT concluded that there is a decrease
in perinatal mortality and early neonatal morbidity associated with cesarean delivery in
nulliparous parturients, additional studies have shown that cesarean delivery can confer risk
to both mother and baby in both current and future pregnancies.5-7 Data has also suggested
that the majority of patients, given the choice would favour a vaginal delivery8,9 and that in
an appropriately selected patient population vaginal breech delivery is still a safe option.10
The optimal mode of delivery of preterm breech infants is also a contentious issue.11 The
RCOG guideline on “Management of Breech Presentation” advises that routine cesarean
section of preterm breeches is not advised.12 Preterm infants were not included in the TBT,
thus evidence relating to their ideal mode of delivery is lacking. Despite this the trial has
had a profound impact on clinicians attitudes to vaginal breech delivery and the preferred
mode of delivery has been shown to be cesarean section.13,14 A randomized controlled trial
to determine the most beneficial mode of delivery in preterm breech presenting infants, has
been attempted and abandoned due to insufficient enrolment.15 Furthermore observational
data relating to maternal and neonatal morbidity associated with vaginal breech delivery of
a preterm infant is not widely reported in the literature. We set out to examine the mode of
delivery of breech infants at gestations prior to 37 weeks, as well as markers of maternal
and neonatal morbidity in those women who had a vaginal breech delivery versus those
delivered by cesarean section.
MATERIALS AND METHODS
This is a retrospective cohort study carried out at the National Maternity Hospital, Holles
St., in Dublin Ireland. The hospital is a large tertiary referral maternity unit, which delivers
approximately 9,000 infants per year. The hospital, located in central Dublin, serves an
urban population. The study included all singleton preterm breech deliveries (<37 weeks
gestation) over an 11-year period from January 1st 2001 to December 31st 2011. Stillbirths
and lethal congenital anomalies were excluded from the study cohort. There was no
change in institutional policy to preterm breech delivery over the course of the study. The
data was gathered as part of continuous hospital wide audit of practice and was hence
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deemed exempt from ethical committee approval by the National Maternity Hospital ethics
committee.
The hospital’s policy regarding breech – presenting infants is that any patient with a breech
presentation at 37-38 weeks’ gestation is counselled and offered external cephalic version
or elective cesarean section at 39 weeks’ gestation. Management of preterm breeches is
judged on an individual case – by – case basis. If a patient arrives to hospital in labor, is
making satisfactory progress with normal fetal monitoring then a vaginal breech delivery
may be attempted provided the patient is counselled regarding potential complications.
Patients are also informed about the possibility for a difficult cesarean delivery due to
descent of the breech into the pelvis in advanced labor.
The primary objective was to compare outcomes of breech presenting preterm infants
according to mode of delivery. We examined the mode of delivery and associated
complications for preterm breech infants at three gestational periods. The gestational
periods investigated were classified as extreme prematurity (24+0 – 27+6 weeks of
gestation), moderate prematurity (28+0 – 31+6 weeks) and finally mild prematurity (32+0 –
36+6 weeks). Gestational age was determined by last menstrual period (LMP), in the event
of patients being unaware of LMP or having an irregular menstrual cycle ultrasonography
was used to determine gestational age.
Labor and delivery characteristics that were analysed included duration of labor (measured
from time of admission to the delivery ward to time of delivery) and method of vaginal
breech delivery i.e. spontaneous, assisted with Mauriceau–Smellie–Veit (MSV), or assisted
via instrumental delivery. Markers of neonatal morbidity for the group of patients delivered
vaginally were compared with those in the group delivered by cesarean section in each
gestational period. Neonatal morbidity was assessed by examining rates of perinatal death
associated with traumatic breech delivery as well as rates of cord pH <7.0, Apgar < 7 at 5
minutes and admission to the neonatal intensive care unit. Maternal morbidity was assessed
by examining the incidence of post–partum hemorrhage (blood loss >500ml and >1000ml)
as well as episiotomy and anal sphincter injury rates.
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Statistical analysis was performed using the χ2 test and Fisher exact test, Odds ratios and
95% confidence intervals were also included. Numbers needed to treat (NNT) to prevent
harm were also calculated. Comparison of means was accomplished with a student’s t –
test. The SPSS software package (version 20.0; SPSS, Chicago, IL) was used; and a 2-tailed
probability value of <0.05 was considered significant.
RESULTS
During the 11 – year study there were 85,785 deliveries, this included 2759 (3.2%)
breech deliveries. A total of 15% (413/2759) of breech infants were <37 weeks gestation.
Approximately 40% (163/413) had a medically indicated pre-labour caesarean delivery
while the remaining 60% (250/413) presented in preterm labour.
The rate of cesarean delivery of all preterm breech infants in labour was 57% (142/250).
A graph of the rate of cesarean delivery among preterm breech presenting infants for each
completed week of gestation from 24+0 to 36+6 can be seen in figure 1. From 24 to 26
weeks gestation the rate of vaginal delivery of breech infants was 85% (23/27). The rate of
cesarean delivery increases from 26+0 and reaches a plateau of approximately 80% at 27
completed weeks gestation where it remains until the end of the 37th week.
Extreme Prematurity (24 – 28 weeks gestation)
A total of 64 breech infants were delivered between 24–28 weeks gestation. The rate of
cesarean delivery was 42.2% (27/64). The majority of those delivered by cesarean section
were not in labour (81.4% [22/27]). A total of 65.6% (42/64) of patients presented in labor
and the rate of vaginal delivery of those in this group was 88.1% (37/42). Of the 37 infants
who delivered vaginally 11 (29%) required the MSV manoeuvre to assist with delivery, no
infant required an operative vaginal delivery. Prior to 26 weeks the rate of vaginal delivery
of those patients who present in labor was 100% (22/22), the perinatal mortality rate was
9.1% (2/22).
The mean duration of labor of those who presented in spontaneous labor and subsequently
delivered vaginally was 91.2 ± 75 mins (range 5 – 414mins). The rate of nulliparity was
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similar among patients delivered vaginally and abdominally (45.9% [20/37] vs. 40.7%
[11/27]; p=0.79). The mean birthweight of the cohort delivered prior to 28 weeks gestation
was 869.6 ± 208.7g. Infants delivered by cesarean section however were found to be
larger than those delivered vaginally (934.2 ± 244.3g vs. 822.5 ± 166.6g; p=0.02). Infants
delivered vaginally were not at increased risk of an Apgar score <7 at 5 mins versus those
who had a cesarean delivery (55.5% [15/27] vs. 45.9% [17/37]; p=0.6). Similarly there was
no difference in the incidence of a cord pH < 7.0 between both groups (9% [2/22] vs. 11.7%
[2/17]; p = 1.0). The rate of perinatal mortality in this gestational cohort was 7.8% (5/64).
Four of the 5 fetal losses took place in women who had a vaginal breech delivery. Three of
the four fetal deaths delivered vaginally were associated with extreme prematurity with two
delivering at 24 weeks and one at 25 weeks gestation. The fourth was delivered at 27 weeks
however the patient had had ruptured membranes since 19 weeks gestation. The baby died
at 2 hours of age. The fetal loss delivered by cesarean section was associated with placental
abruption at 27 weeks and 6 days.
Women who had a cesarean delivery were more likely to have a blood loss greater than
500ml (26% [7/27] vs. 5.4% [2/37]; p=0.02; NNT=2). The incidence of blood loss greater
than 1000ml between the two groups appeared to be greater although it did not reach
statistical significance (11.1% [3/27] vs. 0% [0/37]; p=0.07). The rate of episiotomy in
those patients delivered vaginally was 13.5% (5/37), no patient suffered anal sphincter
injury. A summary of outcomes found in breech deliveries of infants between 24 and 28
weeks gestation can be seen in table 1.
Moderate Prematurity (28 – 32 weeks gestation)
The rate of cesarean delivery increased between 28-32 weeks gestation to 81.9% (86/105).
Similar to the previous gestational epoch the majority of those delivered by cesarean
section were not in labor (80.2% [69/86]). The rate of cesarean delivery of those in labor
was 47.2% (17/36), this was increased when compared with the rate of cesarean delivery
in the previous gestational period (47.2% vs. 11.9%; p=0.0002). Of the 19 infants who
had a vaginal breech delivery between 28 and 32 weeks gestation, 9 (47%) required the
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MSV manoeuvre to assist delivery. No infants required an instrumental delivery. The rate
of nulliparity was similar among patients delivered vaginally and abdominally (52.6%
[10/19] vs. 55.9% [48/86]; p=0.8). There was no difference found in the birthweight of
infants delivered by cesarean section or those delivered vaginally (1367 ± 398g vs. 1415
± 239g; p=0.6). The mean duration of labor of those who delivered vaginally was 48.2 ±
64 mins (Range 2 -237 mins). Infants delivered vaginally were found to have an increased
rate of having an Apgar score of < 7 at 5mins over those who had a cesarean delivery
(31.6% [6/19] vs. 11.6% [10/86]; p=0.03; NNT=3). Infants delivered vaginally were not
however more likely to have a pH < 7.0 (9.1% [1/11] vs. 6.2% [3/48]; p=0.5; NNT=26).
The perinatal mortality rate was 1.9% (2/105), one of these infants was delivered vaginally.
When maternal morbidity was examined women who had a cesarean delivery were more
likely to have a blood loss greater than 500ml (30.2% [23/86] vs. 0% [0/19]; p=0.01;
NNT=2). They were not more likely to have a blood loss of >1000ml (3.5% (3/86) vs. 0%
(0/19); p=1.0). The rate of episiotomy in those patients delivered vaginally was 26.3%
(5/19), no patient suffered anal sphincter injury. A summary of outcomes found in breech
deliveries of infants between 28-32 weeks gestation can be seen in table 2.
Mild Prematurity (32 – 37 weeks gestation)
The cesarean delivery rate between 32-37 weeks gestation was 78.6% (192/244). The rate
of cesarean delivery in labor similar to the previous gestational period was 47% (46/98),
there was no difference when compared with the rate of cesarean delivery in the previous
gestational epoch from 28-32 weeks (47.2% vs. 47%; p=0.97). Of the 52 infants who had
a vaginal breech delivery between 32-37 weeks gestation, 30 (58%) required the MSV
manoeuvre to assist delivery, while 3 (6%) had a forceps assisted – delivery of the after-
coming head. A comparison of rates of vaginal breech delivery of preterm infants for
individual gestational epochs can be seen in table 3. Patients requiring a cesarean delivery
were more likely to be nulliparous than those who had a vaginal delivery (64.6%[124/192]
vs. 40.3%[21/52]; p=0.002). There was no difference in birthweight of infants delivered
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by cesarean section or those delivered vaginally (2388±618g vs. 2420±495g; p=0.72).
The mean duration of labor of those infants who had a vaginal breech delivery was 114.3
± 132 mins. Infants delivered vaginally had an increased risk of having an Apgar score
of <7 at 5mins over those who had a cesarean delivery (19.2%[10/52] vs. 7.8%[15/192];
p=0.03; NNT=5). Infants delivered vaginally were not more likely to have a pH<7.0
(10.2% [4/39] vs. 3.9% [4/104]; p=0.2). The perinatal mortality rate was 0.8% (2/244)
with one of these two infants having a vaginal breech delivery. Those who had a cesarean
delivery were more likely to have a blood loss greater than 500ml (23% [44/192] vs.
3.8% [2/52]; p=0.001; NNT=2), they were not however more likely to have a blood loss
of >1000ml (5.2%[10/192] vs. 1.9%[1/52]; p=0.46). The rate of episiotomy in patients
delivered vaginally was 53.8% (28/52), there were no cases of sphincter injury. A summary
of outcomes found in breech deliveries of infants between 32 and 37 weeks gestation can be
seen in table 4.
DISCUSSION
We have previously published trends in management of breech deliveries at term4
however this study represents a contemporary analysis of management of preterm breech
presentation between 24-37 weeks gestation. From 26 weeks gestation the rate of cesarean
delivery rapidly increased reaching a plateau of circa 80%, which was maintained until 37
weeks gestation.
In the severe prematurity group it was found that the majority of patients who present
in labor prior to 28 weeks gestation deliver vaginally (88%). Between 28 and 37 weeks
gestation the rate of vaginal breech delivery in labor was 47%.
We found that infants between the gestational ages of 28 and 37 weeks who had a vaginal
breech delivery were more likely to have an Apgar score of < 7 at 5 mins, they were not
however more likely to have a low cord pH (<7.0).
Studies have suggested an increased risk of neonatal mortality in vaginal breech deliveries
when compared with cesarean delivery.11,16 This however has been disputed by subsequent
publications.17 The risk of increased rates of neonatal mortality are difficult to quantify as
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while a traumatic vaginal breech delivery, may contribute to an increased risk of neonatal
mortality, sequelae of prematurity in this cohort also play a significant role in neonatal
outcomes.
Over the study there was no change in institutional policy on the management preterm
breech, a limitation that must be considered however is the publication of the term breech
trial in 2001. This may have had an impact on the attitudes of individual clinicians and it is
impossible to quantify this effect.
In our previously published data we have discussed the potential lack of training of
obstetric residents and the possibility of experienced clinicians losing their skills in the
management of vaginal breech delivery. This study demonstrates that vaginal breech
delivery is a frequent challenge in contemporary obstetrics and that it is a necessary
skill that all residents need to develop. Appropriate selection of patients suitable for
trial of vaginal breech delivery must be carried swiftly on their arrival to the delivery
ward and this is best accomplished by involving senior staff in the assessment. Use of
simulation models has potential in the education of residents and the maintenance of skills
in more experienced clinicians. One study has demonstrated that residents were more
knowledgeable and safer in their management of vaginal breech delivery after just one
exposure to a model simulating vaginal breech delivery.18
Vaginal breech delivery of both term and preterm infants remains a necessary skill that
clinicians must endeavour to remain familiar with as these results suggest this is a task they
will be required to carry out many times over their career.
REFERENCES
1 Hickok DE, Gordon DC, Milberg JA, Williams MA, Daling JR. The frequency of
breech presentation by gestational age at birth: a large population-based study. Am J
Obstet Gynecol 1992:166:851-2.
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2 Albrechtson S, Rasmussen S, Irgens LM. Secular trends in peri- and neonatal
mortality in breech presentation Norway 1967-1994. Acta Obstet Gynecol Scand
2000;79:508-12.
3 Hannah ME, Hannah WJ, Hewson SA, Hod- nett ED, Saigal S, Willan AR. Planned
caesarean section versus planned vaginal birth for breech presentation at term:
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4 Hehir MP, O’Connor HD, Kent EM, Fitzpatrick C, Boylan PC, Coulter-Smith S,
Geary MP, Malone FD. Changes in vaginal breech delivery rates in a single large
metropolitan area. Am J Obstet Gynecol 2012;206:498.e1-4.
5 Hemminki E, Merilainen J. Long-term effects of cesarean sections: ectopic
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7 Morrison JJ, Rennie JM, Milton PJ. Neonatal respiratory morbidity and mode
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8 Chong ES, Mongelli M. Attitudes of Singapore women toward cesarean and vaginal
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9 Yogev Y, Horowitz E, Ben-Haroush A, Chen R, Kaplan B. Changing attitudes toward
mode of delivery and external cephalic version in breech presentations. Int J
Gynaecol Obstet 2002;79:221-4.
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10 Alarab M, Regan C, O’Connell MP, Keane DP, O’Herlihy C, Foley ME.
Singleton vaginal breech delivery at term: still a safe option. Obstet Gynecol
2004;103:407-12.
11 Reddy Um, Zhang J, Sun L, Chen Z, Raju TNK, Laughon K. Neonatal mortality
by attempted route of delivery in early preterm birth. Am J Obstet Gynecol 2012;
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12 Hofmeyr GJ, Impey LWM. RCOG green top guideline No. 20b: Management breech
presentation. 2006. www.rcog.org.uk/guidelines
13 Sullivan EA, Moran K, Chapman M. Term breech singletons and caesarean
section: a population study, Australia 1991-2005. Aust N Z J Obstet Gynaecol.
2009;49:456-60.
14 Hartnack Tharin JE, Rasmussen S, Krebs L. Consequences of the Term Breech Trial
in Denmark. Acta Obstet Gynecol Scand 2011;90: 767-71.
15 Penn ZJ, Steer PJ, Grant A. A multicenter randomized controlled trial comparing
elective and selective cesarean section for the delivery of the preterm breech infant.
BJOG 1996;103:684-9.
16 Grravenhorst JB, Schreuder AM, Veen S, Brand R, Verloove-Vanhorick SP, Verwiej
RA, van Zeben-van der Aa DM, Ens-Dokkum MH. Breech delivery in very preterm
and very low birthweight infants in The Netherlands. Br J Obstet Gynaecol 1993
May;100(5):411-5.
17 Kayem G, Baumann R, Goffinet F, El Abiad S, Vile Y, Cabrol D, Haddad B. Early
preterm breech delivery: is a policy of planned vaginal delivery associated with
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Epub 2008 Feb 1.
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18 Deering S, Brown J, Hodor J, Satin AJ. Simulation training and resident
performance of singleton vaginal breech delivery. Obstet Gynecol. 2006
Jan;107(1):86-9.
FIGURE LEGEND
Figure 1 shows the rate of cesarean delivery of preterm breech presenting infants.
Increasing gestational age is shown on the X-axis in increments of completed
gestational weeks.
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Table 1. Outcomes associated with delivery of a
breech – presenting infant between 24+0 and 27+6
Characteristic VaginalDelivery (N=37)
LSCS(N=27)
P – Value
Gestational Age (Days) 186.1 ± 7 178.5 ± 6.9 < 0.0001
Birthweight 934.2 ± 244.3g 822.5 ± 166.6g 0.02
Nulliparity 45.9% [20/37] 40.7 [11/27] NS
Apgar < 4 @ 5mins 19.4% [6/37] 28.6% [6/27] NS
Apgar < 7 @ 5 mins 45.9% [17/37] 55.5% [15/27] NS
pH < 7.0 9% [2/22] 11.7% [2/17] NS
Maternal BloodLoss >500ml
5.4% [2/37] 26% [7/27] 0.02
Maternal BloodLoss >1000ml
0% [0/37] 11.1% [3/27] 0.07
Legend
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Table 2. Outcomes associated with delivery of a
breech – presenting infant between 28+0 and 31+6
Characteristic VaginalDelivery (N=19)
LSCS(N=86)
P – Value
Gestational Age (Days) 211.2 ± 7.8 209.8 ± 8.6 NS
Birthweight 1415 ± 239g 1367 ± 398g NS
Nulliparity 52.6% [10/19] 55.9% [48/86] NS
Apgar < 4 @ 5mins 10.5% [2/19] 3.5% [3/86] NS
Apgar < 7 @ 5 mins 31.6% [6/19] 11.6% [10/86] 0.03
pH < 7.0 9.1% [1/11] 6.2% [3/48] NS
Maternal BloodLoss >500ml
0% [0/19] 30.2% [23/86] 0.01
Maternal BloodLoss >1000ml
0% (0/19) 3.5% (3/86) NS
Legend
NS = Non – significant; p > 0.05
Table 3. Rates of vaginal breech delivery of preterm infants in spontaneous laboraccording to gestational period
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Comparison with previousgestational epoch
GestationalPeriod
Vaginal Delivery P- Value Odds Ratio;95% CI
ExtremePrematurity
(24+0 – 27+6)
88.1% (37/42) NA NA
ModeratePrematurity(28+0-31+6)
47.2% (17/36) 0.0002 8.2; 2.6 – 25.8
Mild Prematurity(32+0 – 36+6)
47% (46/98) 0.97 1.01; 0.47 – 2.2
LegendCI = Confidence IntervalNA= Not available
Table 4. Outcomes associated with delivery of a
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Characteristic VaginalDelivery (N=52)
LSCS(N=192)
P – Value
Birthweight 2388 ± 618g 2420 ± 495g NS
Nulliparity 40.3% [21/52] 64.6% [124/192] 0.002
Apgar < 4 @ 5 mins 5.8% [3/52] 1.0% [2/192] NS
Apgar < 7 @ 5 mins 19.2% [10/52] 7.8% [15/192] 0.03
pH < 7.0 10.2% [4/39] 3.9% [4/104] NS
Maternal BloodLoss >500ml
3.8% [2/52] 23% [44/192] 0.001
Maternal BloodLoss >1000ml
1.9% [1/52] 5.2% [10/192] NS
Legend
NS = Non – significant; p > 0.05
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