Use of proton pump inhibitors during pregnancy: A systematic review and meta-analysis of congenital malformations.

Use of proton pump inhibitors (PPI) are common among pregnant women to relieve gastrointestinal symptoms. The number of exposed pregnancies is therefore considerable, and a recent meta-analysis (MA) from 2020 raised concern about their teratogenicity. The aim of the study was to provide a MA of the risk of major congenital malformations (MCM) after PPI exposure during the first trimester of pregnancy. A systematic review and random-effects model approach were performed using a collaborative WEB-based meta-analysis platform (metaPreg.org) with a registered protocol (osf.io/u4gva). The primary outcome was the incidence of overall MCM. The secondary outcomes of interest were specific MCM reported by at least three studies. All comparative studies assessing these outcomes in PPI exposed pregnancies were searched from inception to April 2022. From the 211 initially identified studies, 11 were included in the MA. The pooled odds ratio (OR) for the primary outcome showed no significant results based on 5 618 exposed pregnancies (OR 1.10, 95% CI [0.95;1.26]; I²=0%). Similarly, no result was significant for the secondary outcomes. The total exposed sample size ranged from 3 161-5 085; OR ranged between 0.60 and 1.92; heterogeneity was between 0% and 23%. Based on the results of the present MA, first trimester PPI exposure was not associated with a significantly increased risk of overall or specific MCM. However, this MA included only observational studies which are prone to bias and there were insufficient data to evaluate PPI at a substance level. Future studies are needed to address this concern.