Calcium Channel Blocker Exposure in Late Pregnancy and the Risk of Neonatal Seizures

OBJECTIVE: To assess whether maternal calcium channel blocker exposure during late pregnancy is independently associated with neonatal seizures after carefully controlling for confounding factors. METHODS: Data were derived from the Medicaid Analytic eXtract for the years 2000–2007 and included 2,529,636 completed pregnancies. We compared the risk of neonatal seizures among neonates who were born to women who took calcium channel blockers in the final month of pregnancy to the risk in neonates born to women who did not use calcium channel blockers. Confounding was addressed through the use of propensity score matching. RESULTS: A total of 22,908 (0.91%) pregnancies included exposure to calcium channel blockers during the final month of pregnancy. Neonatal seizures occurred in 53 (0.23%) neonates born to mothers exposed to calcium channel blockers and in 4,609 (0.18%) neonates of unexposed women (unadjusted odds ratio [OR] 1.26, 95% confidence interval [CI] 0.96–1.65). After accounting for confounders, there was no increase in risk of neonatal seizures associated with calcium channel blocker exposure (OR 0.95, 95% CI 0.70–1.30). This null finding was robust across multiple sensitivity analysis. CONCLUSION: In this large, carefully controlled, population-based cohort study, there was no significant increase in the risk of neonatal seizures in neonates attributable to maternal calcium channel blocker exposure in late pregnancy. The results suggest that calcium channel blockers can be used by obstetricians in late pregnancy without excess concern about this neonatal complication. LEVEL OF EVIDENCE: II