Objective: It has been proposed recently that pre-eclampsia (PE) may originate 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 have an increased risk of PE. The aim of this systematic review was to investigate the risk of PE in pregnant women with CHD.
Methods: 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. Randomized controlled trials and observational studies (prospective or retrospective cohorts) of pregnant women with a history of CHD were sought. The main outcome was the incidence of PE (including eclampsia and HELLP syndrome). For quality assessment of the included studies, two reviewers assessed independently the risk of bias. For the meta-analysis, the incidence of PE in pregnancies (those beyond 20 weeks' gestation) was calculated using single-proportion analysis by random-effects modeling (weighted by inverse variance). Heterogeneity between studies was assessed using the χ2 (Cochran's Q), tau2 and I2 statistics. Subgroup analysis was performed, and meta-regression was used to assess the influence of several covariates on the pooled results.
Results: A total of 33 studies were included in the meta-analysis, including 40 449 women with CHD and a total of 40 701 pregnancies. The weighted incidence of PE was 3.1% (95% CI, 2.2-4.0%), with true-effect heterogeneity of 93% according to I2 , and no publication bias found. No difference was found in the weighted incidence of PE between studies including cyanotic CHD vs those excluding (or not reporting) cyanotic CHD (2.5% (95% CI, 1.6-3.4%) vs 4.1% (95% CI, 2.4-5.7%); P = 0.0923). Meta-regression analysis showed that the only cofactor that significantly influenced the incidence of PE in each study was the reported incidence of aortic stenosis; studies with a higher incidence of aortic stenosis had a higher incidence of PE (estimate: 0.0005; P = 0.038).
Conclusions: We failed to demonstrate an incidence of PE above the expected baseline risk in women with CHD. This observation contradicts the theory of the cardiac origin of PE. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.
Keywords: HELLP syndrome; congenital heart disease; eclampsia; gestational hypertension; pre-eclampsia; single-proportion meta-analysis; small-for-gestational age.
© 2020 International Society of Ultrasound in Obstetrics and Gynecology.