A cohort study was conducted among pregnant women enrolled in the Medicaid program during 2000–2007. The prevalence of congenital malformations was compared between infants born to women who were (n = 1152) and were not (n = 885,844) taking a statin medication during the first trimester of pregnancy.

Among statin users, 45.1% had a history of diabetes, compared with 3.1% of nonusers.

Among infants born to women who were statin users, the prevalence of a malformation (all types combined) was 6.34%, in contrast to 3.55% among other infants (relative risk = 1.79). After adjustment for the presence of maternal diabetes, the relative risk was 1.34.