Incidence of pre‐eclampsia and other perinatal complications among women with congenital heart diseases: systematic review and meta‐analysis

OBJECTIVE It has recently been proposed that preeclampsia (PE) may be originating from maternal cardiac maladaptation rather than primary placental insult. As congenital heart disease (CHD) is associated with reduced adaptation to the hemodynamic needs of pregnancy, it is hypothesized that women with CHD would have an increased risk of PE. The aim of this study was to investigate the risk of PE in women with CHD. DATA SOURCES A systematic search was performed to identify relevant studies published in English, Spanish, French, Italian, Chinese, or German with no time restrictions, using databases such as PubMed, Web of Science, and Scopus. STUDY ELIGIBILITY CRITERIA Randomized controlled trials and observational studies (prospective and retrospective cohorts) of pregnant women with a history of CHD were selected. STUDY APPRAISAL AND SYNTHESIS METHODS The main outcome was the incidence of PE (including eclampsia and HELLP syndrome). For quality assessment, two reviewers independently assessed the risk of bias of the included studies. For the meta-analysis, the incidence of PE in completed pregnancies (those beyond 20 weeks' gestation) was calculated using a single-proportion analysis by random-effects modeling (weighted by inverse-variance). Heterogeneity between studies was assessed using the X2 (Cochrane Q), H, and I2 statistics. Subgroup analyses were performed as well as meta-regression to explain the influence of several covariates on the pooled results. RESULTS After the systematic review, a total of 33 studies were retained for the meta-analysis, comprising 40,449 women with CHD and a total of 40,701 completed pregnancies. The incidence of PE was 3.1% (95% CI: 2.2-4.0%), true-effect heterogeneity was 93% by I2 , and no publication bias was found. No differences were found in the incidence of PE between studies including cyanotic CHD vs. studies without cyanotic CHD (2.5% [95% CI: 1.6%-3.4%] vs. 3.8% [95% CI: 2.4%-5.2%]; p=0.112). The meta-regression analysis showed that the only cofactor significantly influencing the incidence of PE was the incidence of aortic stenosis reported in each article; articles with a higher incidence of aortic stenosis had a higher incidence of PE (estimate: 0.0005; p=0.038). CONCLUSIONS In women with CHD, we have failed to demonstrate an incidence of PE above the expected baseline, an observation that disagrees with the theory of the cardiac origin of PE. This article is protected by copyright. All rights reserved.