Maternal use of proton pump inhibitors during early pregnancy and the prevalence of hypospadias in male offspring.

Proton pump inhibitors (PPIs) are increasingly used in reflux disease treatment also among pregnant women. Hypospadias prevalence is increasing and the birth defect is diagnosed in 0.3%-0.8% of male births, but the association with maternal PPI use during pregnancy is virtually unknown. Therefore, we decided to estimate the hypospadias risk in male offspring after maternal PPI use during pregnancy. We used Danish nationwide registries to conduct a population-based prevalence study including all live-born boys from 1997 through 2009. Maternal PPI use was classified according to exposure time: early pregnancy (30 days before conception through the end of the first trimester) and entire pregnancy (30 days before and throughout pregnancy). Outcome was defined as a hospital hypospadias diagnosis recorded any time after delivery. We calculated prevalence ratios and 95% confidence intervals associating maternal PPI use with hypospadias in male offspring using Cox proportional hazard regression analysis and adjusted for confounding factors. We identified a total of 430,569 live-born boys of whom 2926 were exposed to maternal PPI use during early pregnancy. Among the exposed boys, 20 (0.7%) were diagnosed with hypospadias, whereas 2683 (0.6%) of the nonexposed had hypospadias (adjusted prevalence ratio = 1.1; 95% confidence interval, 0.7-1.7). A total of 5227 boys were exposed during the entire pregnancy, and 32 (0.6%) had hypospadias corresponding to a prevalence ratio of 1.0 (95% confidence interval, 0.7-1.4). The subanalysis restricted to omeprazole exposure showed similar results. We thus conclude that maternal PPI use during pregnancy was not associated with hypospadias in boy offspring.