Purpose
Calcium channel blockers and beta-blockers are widely used during pregnancy, but data on their safety for the developing infant is scarce. We used population-based data from 5 HMOs to study risks for perinatal complications and congenital defects among infants exposed in-utero.
Methods
We studied women older than 15 years delivering an infant between 1/1/96 to 12/31/00, who had been continuously enrolled with prescription drug coverage for >= one year prior to delivery. Information on prescription drug dispensings, inpatient and outpatient diagnoses and procedures was obtained from automated databases at each HMO.
Results
There were 584 full-term infants exposed during pregnancy to beta-blockers and 804 full-term infants exposed to calcium-channel blockers, and over 75,000 unexposed mother-infant pairs with >= 30 days follow-up. Infants exposed to beta-blockers in the third trimester of pregnancy had over three-fold increased risk for hypoglycemia (RR 3.1; 95% CI 2.2, 4.2) and an approximately two-fold increased risk for feeding problems (RR 1.8; 95% CI 1.3, 2.5). Infants exposed to calcium-channel blockers in the third trimester had an increased risk for seizures (RR 3.6 95% CI 1.3, 10.4). Chart review confirmed the majority of the exposed seizure and hypoglycemia cases. There were no increased risks for congenital anomalies among either group of infants, except for the category of upper alimentary tract anomalies; this increased risk was based on only two exposed cases.
Conclusions
Infants whose mothers receive beta-blockers are at increased risk for neonatal hypoglycemia, while those whose mothers take calcium-channel blockers are at increased risk for neonatal seizures.