Risk of congenital anomalies in pregnant users of statin drugs

What is already known about this subject • Cholesterol is known to be essential for fetal development. • Statins, which inhibit cholesterol production, have therefore been considered as potential teratogens and are contraindicated in pregnancy. • Data available thus far on the risks of congenital anomalies associated with statin therapy have come from non‐analytic postmarketing surveillance studies. • Given the increasing use of statins in women of childbearing age, there is a need for a population‐based study on the risks of congenital anomalies associated with gestational statin use. What this study adds • In this pharmacoepidemiological study, we determined the risk of congenital anomalies in women who filled prescriptions for statins during the first trimester of pregnancy, compared with women who had stopped statins before pregnancy or those who used fibrates during pregnancy. • We found no evidence of an increased risk of fetal anomalies among first‐trimester statin users, or any discernable pattern of congenital anomalies among live births. • However, in the absence of outcome data on nonlive births, conclusions remain uncertain. Aims Evidence from animal studies suggests that statin medications should not be taken during pregnancy. Our aim was to examine the association between the use of statins in early pregnancy and the incidence of congenital anomalies. Methods A population‐based pregnancy registry was built. Three study groups were assembled: women prescribed statins in the first trimester (group A), fibrate/nicotinic acid in the first trimester (group B) and statins between 1 year and 1 month before conception, but not during pregnancy (group C). Among live‐born infants, we selected as cases infants with any congenital anomaly diagnosed in the first year of life. Controls were defined as infants with no congenital anomalies. The rate of congenital anomalies in the respective groups was calculated. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were also calculated. Results Our study group consisted of 288 pregnant women. Among women with a live birth, the rate of congenital anomalies was 3/64 (4.69%; 95% CI 1.00, 13.69) in group A, 3/14 in group B (21.43%; 95% CI 4.41, 62.57) and 7/67 in group C (10.45%; 95% CI 4.19, 21.53). The adjusted OR for congenital anomalies in group A compared with group C was 0.36 (95% CI 0.06, 2.18). Conclusion We did not detect a pattern in fetal congenital anomalies or evidence of an increased risk in the live‐born infants of women filling prescriptions for statins in the first trimester of pregnancy. Conclusions, however, remain uncertain in the absence of data from nonlive births.