Objective: To study delivery outcome after maternal use of acid-suppressing drugs during early pregnancy.
Design: Cohort study of women identified by interview in early pregnancy.
Population: Sweden women giving birth from 1995 to early 1997.
Methods: Comparison of infants exposed to acid-suppressing drugs with all births in 1995-1996.
Main outcome measures: Presence of congenital malformations.
Results: Proton pump blockers were used by 275 women, H2 receptor antagonists by 255 women, and both categories of drugs by 20 women. No effect of the use of omeprazole or H2-receptor antagonists on the rate of congenital malformations could be demonstrated.
Conclusions: Though a teratogenic effect of these drugs cannot be completely ruled out, the individual risk after exposures during the first trimester seems to be negligible.