Background: Pre-eclampsia is a syndrome unique to pregnancy, and usually associated with hypertension and proteinuria. It affects 4-5% of pregnancies and is an important cause of maternal and perinatal mortality and morbidity. Its precise etiology is still unknown. Therefore, prediction of high risk pregnancies and prevention of the disease remain difficult. A number of tests are currently being used to predict pre-eclampsia, varying from biochemical tests (spot proteinuria) to historical factors (parity). Their precise predictive power is often unclear. This makes it even more difficult to effectively target preventive strategies. There are several Cochrane reviews for prevention of pre-eclampsia. Gaps remain, however, and the assessment of risk factors is not consistent within reviews, reflecting previous uncertainty about prediction of risk.
Objectives: 1. To determine, among normotensive women in early pregnancy, the accuracy of various tests (history, examination and investigations) for predicting the later development of pre-eclampsia and related complications. The test results of the better tests may be used for risk stratification and improved targeting of vigilant monitoring and treatment. 2. To determine the effectiveness and safety of interventions to prevent pre-eclampsia and its complications and to assess, where possible, how this varies with risk.
Methods: 1. To identify relevant literature, a sensitive search strategy including a pre-eclampsia text string, a diagnostic accuracy string and an etiologic string was used for systematic electronic searches, performed in MEDLINE, EMBASE, Cochrane Library and MEDION database. Individual experts were contacted. Reference lists of selected articles will be checked. No language restrictions will be applied. Inclusion, quality assessment and data extraction will be performed by two independent reviewers according to predefined and pilot tested criteria, which will be tailor-made for each separate test. Disagreements will be resolved by consensus and/or arbitration involving a third reviewer. Data analysis will explore heterogeneity. Meta-regression methods will be applied to explain sources of heterogeneity. 2. To agree with existing reviewers a standard core protocol for Cochrane reviews of interventions to prevent pre-eclampsia. To then update existing reviews and to conduct new reviews for any identified topics not yet covered. Finally to prepare summary reviews of the main categories of intervention, stratified by risk factors.
Results: Systematic searches provided 15,375 references. We estimated that approximately 2,300 (15%) possibly relevant test accuracy studies and reviews will be selected as full text papers. The selection process is currently in progress. The core protocol for Cochrane reviews of interventions is currently being drafted.
Conclusions: Results of the first test accuracy reviews will be presented, illustrating issues of searching, data management, study validity, and data-analysis. Progress with the Cochrane reviews will be summarised.
Acknowledgements: Academic Medical Center (NL), Department Obstetrics & Gynaecology: Joris van der Post, Ben Willem Mol Birmingham Women s Hospital (UK): Janesh Gupta, Khalid Khan