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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 National 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 important 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 Surveillance Unit (BPSU) has developed a reliable method to study uncommon disorders of childhood. BPSU surveys have informed policy on antenatal screening, documented the association between Reye's syndrome and aspirin, identified the risks of faulty packaging of chemistry sets9 and investigated 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 hospital with a consultant obstetric unit will nominate four individuals (obstetrician, midwife, anaesthetist and perinatal risk management co-ordinator) who will be sent a monthly report card with a list of conditions currently under surveillance (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.

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Figure 1. UKOSS report card.

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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 antenatal pulmonary embolism. However, they will be treated for these disorders throughout the remainder of their pregnancy 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 information. They seek confirmation of the appropriate case definition and additional information on risk factors, management 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, UKOSS will 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 hysterectomy, 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 newsletters, an annual report and peer-reviewed publications.

How will future studies be identified?

  1. Top of page
  2. How will future studies be identified?
  3. Initial studies
  4. References

Applications will be invited from clinicians and other researchers for inclusion of suitable studies into the surveillance system. They will be considered by the UKOSS steering 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 (prospective descriptive, cohort or case–control studies).
  • Other sources of information exist to enhance and/or assess completeness of data collection.

Initial studies

  1. Top of page
  2. How will future studies be identified?
  3. Initial studies
  4. References

The initial conditions under surveillance will be acute fatty liver, amniotic fluid embolism, antenatal pulmonary embolism, eclampsia, peripartum hysterectomy and tuberculosis in pregnancy. Some of these disorders (antenatal 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 because 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 significantly 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, midwives 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 useful for the future care of pregnant women and their babies.

References

  1. Top of page
  2. How will future studies be identified?
  3. Initial studies
  4. References