Background: Both angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin receptor antagonists (ARBs) have been reported to be associated with an excess of congenital abnormalities in infants born to women who took these drugs in pregnancy.

Methods: To investigate this possible association further, we have examined the outcome in 91 pregnancies in which the mother took either an ACE-I (n = 71) or an ARB (n = 20) in early pregnancy. We also examined the United Kingdom adverse drug reaction reporting system to assess the total number of reported associations of ACE-I or ARB use in pregnancy and congenital anomalies reported.

Results: Eight (8.8%) of the pregnancies led to an infant with a developmental anomaly, but all save one of these (craniosynostosis with tower skull) anomalies were considered to be relatively minor. The adverse drug reaction reporting system revealed a total of 43 reported defects in women taking an ACE-I and 12 in women taking an ARB.

Conclusion: We have not found any convincing excess of congenital anomalies in women taking angiotensin-blocking drugs in early pregnancy. However, this does not exclude the possibility that ACE-I or ARB use in pregnancy might lead to adverse obstetrical outcomes. Until this matter is settled, we support recommendations that these drugs should not be used in pregnancy or in women who are likely to become pregnant.