COMMENTARY

The UK Obstetric Surveillance System for raredisorders of pregnancy

A new UK Obstetric Surveillance System (UKOSS) has

recently been launched to investigate uncommon disorders

of pregnancy. UKOSS is a joint initiative of the Royal

College of Obstetricians and Gynaecologists and the Na-

tional Perinatal Epidemiology Unit and has the backing of

the Royal College of Midwives, the Faculty of Public

Health, the Health Protection Agency and the Department

of Health Patient Safety Research Programme.

Many uncommon disorders of pregnancy are difficult to

study because routine information sources are unreliable,1,2

and comprehensive studies, such as the BEST survey of

eclampsia in 1992,3 require a large collaboration to identify

relatively few cases. Information requests from multiple

sources about different problems can overburden reporting

clinicians.

Many rare disorders are also ‘near-miss’ events, ‘a severe

life-threatening obstetric complication necessitating an

urgent medical intervention in order to prevent likely death

of the mother’.4 The 50 years5 of triennial Confidential

Enquiries into UK maternal deaths have led to many im-

portant changes in care, but the authors of recent reports5,6

have suggested that study of ‘near-miss’ events may be

useful. The reporting can be faster, and the number of cases

studied larger, than when deaths alone are considered. The

quality of care in maternal deaths and near-misses can be

compared,7 risk factors identified and information to

improve service planning provided.8

Over the last 20 years the British Paediatric Surveil-

lance Unit (BPSU) has developed a reliable method to study

uncommon disorders of childhood. BPSU surveys have in-

formed policy on antenatal screening, documented the as-

sociation between Reye’s syndrome and aspirin, identified

the risks of faulty packaging of chemistry sets9 and inves-

tigated concerns about vitamin K therapy,10 water-births11

and variant CJD in British children.12

UKOSS will use similar methods to the BPSU, namely

a prospective monthly case-collection scheme. Each hospi-

tal with a consultant obstetric unit will nominate four indi-

viduals (obstetrician, midwife, anaesthetist and perinatal

risk management co-ordinator) who will be sent a monthly

report card with a list of conditions currently under surveil-

lance (Fig. 1). Only conditions with an estimated incidence

of fewer than one in 2000 births will be surveyed, and thus

the most common response will be a nil return. The methods

to identify women who should be reported to UKOSS may

include discussing the list at regular perinatal mortality

and morbidity meetings. Conditions that are on existing

perinatal risk ‘trigger event’ lists will be notified already to

the perinatal risk co-ordinator. Women with fatal disorders

will be identified through CEMACH midwives.

Women affected by some of the conditions studied will

not necessarily be seen at the time of diagnosis in obstetric

departments; for example, women with tuberculosis or an-

tenatal pulmonary embolism. However, they will be treated

for these disorders throughout the remainder of their preg-

nancy and unless they lose the pregnancy at an early stage

will be cared for by obstetric and midwifery staff after the

acute event. In order to ensure complete data collection,

reporting staff will be asked to notify women with these

disorders as soon as they become aware of the condition,

whether or not they were caring for the woman at the time

of her first diagnosis.

On receiving a case report (return of the monthly card

mailing), the UKOSS team will dispatch a form to collect

more detailed information. These have been developed

individually for each condition and are designed to be

short and easily completed from a woman’s case notes

without requiring reference to any other sources of infor-

mation. They seek confirmation of the appropriate case

definition and additional information on risk factors, man-

agement and outcomes according to the protocol relating

to each condition. UKOSS will not collect any personally

identifiable information, such as names, addresses, dates

of birth or hospital numbers. Reporting clinicians will only

be asked to keep their own record of the names of women

they have reported, in order that they can retrieve the

woman’s case notes to complete the data collection form.

The London Multi-centre Research Ethics Committee has

approved the collection of anonymised information in this

way without seeking the consent of individual women.

In order to perform case–control studies, UKOSSwill also

collect anonymised information on control women for some

surveys. For these studies only, clinicians who report a case

will also be asked to identify one or two appropriate control

women and complete a similar data collection form from

their case notes. The process of selecting control women will

be individual for each study. For example, for one of the

studies running during the first year, peripartum hysterecto-

my, clinicians will be asked to identify the two women who

delivered in the same hospital immediately before the case

was delivered. Results will be presented in quarterly news-

letters, an annual report and peer-reviewed publications.

BJOG: an International Journal of Obstetrics and GynaecologyMarch 2005, Vol. 112, pp. 263–265

D RCOG 2005 BJOG: an International Journal of Obstetrics and Gynaecology www.blackwellpublishing.com/bjog

DOI: 10.1111/ j .1471-0528.2005.00609.x

How will future studies be identified?

Applications will be invited from clinicians and other

researchers for inclusion of suitable studies into the surveil-

lance system. They will be considered by the UKOSS steer-

ing committee, which consists of representatives from the

Royal College of Obstetricians and Gynaecologists, the

Royal College of Midwives, the Health Protection Agency,

the Faculty of Public Health, lay and other professional

representatives. The committee will meet every four months

to consider applications for the inclusion of new studies into

the scheme, and the conduct of existing studies. Potential

studies will be considered against the following criteria:

� The condition is an important cause of maternal or

perinatal morbidity and/or mortality.� The condition is an uncommon disorder of pregnancy,

thus inclusion within the study programme of UKOSS

will not impose too great a burden on reporting clinicians

(usually no more than one case per 2000 births annually

in the UK).� The research questions posed by the study can be

suitably addressed using the UKOSS methodology (pro-

spective descriptive, cohort or case–control studies).� Other sources of information exist to enhance and/or

assess completeness of data collection.

Initial studies

The initial conditions under surveillance will be acute

fatty liver, amniotic fluid embolism, antenatal pulmonary

embolism, eclampsia, peripartum hysterectomy and tuber-

culosis in pregnancy. Some of these disorders (antena-

tal pulmonary embolism, eclampsia, acute fatty liver and

amniotic fluid embolism) have been identified by the

recent CEMACH report5 as leading causes of maternal

mortality. Peripartum hysterectomy will be included be-

cause of the potential for an increase in incidence in the

light of the rise in caesarean section rates. Tuberculosis is

rising in incidence generally,13 and small hospital-based

studies suggest that there are important differences in the

epidemiology of TB occurring in pregnancy compared

with the non-pregnant population, which impact signifi-

cantly on diagnosis and management.14 A UKOSS study

will establish whether this is the pattern nationwide and

identify current diagnostic and management practices.

Most conditions will be surveyed for one year, although

those which affect extremely small numbers of women

may be surveyed over a longer term to identify sufficient

numbers for valid conclusions to be drawn.

UKOSS is an active partnership with obstetricians, mid-

wives and anaesthetists and will depend on reliable and

complete case identification and data collection to provide

accurate information. In return the findings will be reported

promptly. We encourage all researchers to contact the

UKOSS team if they have a suggestion for a UKOSS study.

We can help generate an appropriate research proposal. We

hope that contributing to UKOSS will become as much a

part of obstetric practice as reporting to the BPSU is part of

paediatric practice, and that the research it produces as use-

ful for the future care of pregnant women and their babies.

Marian Knight,a Jennifer J. Kurinczuk,a Derek Tuffnell,b

Peter BrocklehurstaaNational Perinatal Epidemiology Unit, University of Oxford,

Old Road Campus, Oxford, UKbBradford Hospitals NHS Trust, Duckworth Lane, Bradford,

UK

Fig. 1. UKOSS report card.

264 COMMENTARY

D RCOG 2005 BJOG: an International Journal of Obstetrics and Gynaecology 112, pp. 263–265

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