Angiotensin-Converting–Enzyme Inhibitors During Early Pregnancy Aren't Significantly Associated with Fetal Malformations

Although angiotensin-converting–enzyme (ACE) inhibitors are teratogenic when used during late pregnancy, early exposure was not thought to be harmful until a 2006 study showed an association between first-trimester use and excess risk for congenital anomalies. Now, investigators have conducted a population-based cohort study in 465,745 mother–infant pairs from a large health plan in California to determine if first-trimester ACE inhibitor exposure is associated with risk for fetal malformations beyond that associated with use of any antihypertensive medication or with hypertension alone.

ACE inhibitors were dispensed in 1.6 per 1000 pregnancies, and other antihypertensives were given in 38 per 1000 pregnancies. In adjusted analysis, use of A…