• birth defects;
  • calcium channel blockers;
  • case-control study;
  • epidemiology;
  • pregnancy

Aim. Calcium channel blockers given to pregnant rats have shown an increased prevalence of digital and limb defects and their safety in pregnant women has thus been questioned. We examined the risk of malformations following exposure in utero to calcium channel blockers.

Method. We conducted a nationwide case-control study based on the Hungarian Case-Control Surveillance of Congenital Abnormalities and identified 22,865 cases with congenital abnormalities and 31,151 population controls during the period 1980–1996. Data on drug exposure were obtained from official questionnaires and obligatory prenatal care logbooks.

Results. Among the cases, 586 mothers (2.6%) had been exposed to calcium channel blockers during pregnancy compared with 907 controls (2.4%). The overall prevalence ratios for 17 congenital abnormalities varied between 1.1 and 1.4, and there was no significant increased risk of limb deficiencies or other congenital abnormalities.

Conclusion. Our data did not indicate an increased prevalence of congenital abnormalities in offspring exposed to calcium channel blockers in utero.