Prospective assessment of pregnancy outcome following first trimester exposure to benzodiazepines

Background: The lack of consensus regarding the safety of benzodiazepine (BDZ) exposure in pregnancy has led many women to terminate an otherwise wanted pregnancy. Counselling clinicians are confronted with published data that describe a statistical association between fetal BDZ exposure and cleft lip and/or palate, but other data fail to demonstrate similar findings. OBJECTIVE: To compare pregnancy outcome and rate of birth defects between a BDZ-exposed group and controls. Design: The cases were prospectively collected and pregnancy outcome was recorded on an offspring follow-up form by a trained team member during a follow-up telephone interview. Results: Pregnancy outcome was assessed for 137 cases and 137 controls. Cases were exposed to low dose BDZ, and the most commonly reported indication was anxiety. Eighty-eight per cent used only one BDZ in pregnancy and 127 of the 137 took BDZ during the period of organogenesis only. No statistical difference in the rates of major birth defects, reported miscarriages or elective abortions was found between the groups. Of the live births, there were no intergroup differences in maternal weight gain, birth weight or gestational age at delivery. Exposed infants attained developmental milestones at ages similar to those of infants of the control group. Conclusions: Not a single case of cleft lip or palate in the 106 live born infants was identified. The present study failed to detect an increased risk of major congenital defects following first trimester exposure to BDZ as a class.