A total of seven studies were included in the review. Of the 134,940 patients, 1,530 were exposed to proton pump inhibitors and 133,410 were not exposed to proton pump inhibitors. The study quality score (percentage) ranged from 66% to 72%. Publication bias was absent.
Proton pump inhibitors were not considered to be associated with an increased risk for major congenital birth defects (OR 1.12, 95% CI 0.86 to 1.45; seven studies), spontaneous abortions (OR 1.29, 95% CI 0.84 to 1.97; two studies) or preterm delivery (OR 1.13, 95% CI 0.96 to 1.33; five studies). The use of omeprazole was not associated with an increased risk for congenital malformations (OR 1.17, 95% CI 0.90 to 1.53; six studies). There was no evidence of statistical heterogeneity.