Metformin exposure in first trimester of pregnancy and risk of all or specific congenital anomalies: exploratory case-control study

Abstract

No evidence was found for an increased risk of all non-genetic congenital anomalies combined following exposure to metformin during the first trimester, and the one significant association was no more than would be expected by chance. Further surveillance is needed to increase sample size and follow up the cardiac signal, but these findings are reassuring given the increasing use of metformin in pregnancy.