Prosthetic heart valves in pregnancy: a systematic review and meta-analysis protocol

BACKGROUND: Advances in surgical technique, prosthetic heart valve design, and anticoagulation have contributed to an overall improvement in morbidity and mortality in women with heart valve prostheses as well as increased feasibility of pregnancy. Previous work investigating the pregnancies of women with prosthetic valves has been directed largely toward understanding the influence of anticoagulation regimen. There has been little investigation on maternal and infant outcomes. The objective of this systematic review will be to assess the outcomes of pregnancy in women with heart valve prostheses in contemporary populations. METHODS/DESIGN: A systematic search of Medline, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Cochrane Library will be undertaken. Article titles and abstracts will be evaluated by two reviewers for potential relevance. Studies that include pregnancies occurring from 1995 onwards and where there are six or more pregnancies in women with heart valve prostheses included in the study population will be reviewed for potential inclusion. Primary outcomes of interest will be mortality (maternal and perinatal). Secondary outcomes will include other pregnancy outcomes. No language restrictions will be applied. Methodological quality and heterogeneity of studies will be assessed. Data extraction from identified articles will be undertaken by two independent reviewers using a uniform template. Meta-analyses will be performed to ascertain risk of adverse events and, where numbers are sufficient, by type of prosthesis and location as well as other subgroup analyses. DISCUSSION: Estimates of the risk of adverse events in recent pregnancies of women with heart valve prosthesis will provide better information for counselling and decision making. Given the improvements in prognosis of heart valve prosthesis recipients and the paucity of definitive data regarding optimal pregnancy management for these women, review of this topic is pertinent. REVIEW REGISTRATION: This protocol has been registered with the international prospective register of systematic reviews (PROSPERO) as number CRD42013006187, accessible online at http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42013006187#.Utk7qNJ9Lf8.