A population-based case-control study of oral chlordiazepoxide use during pregnancy and risk of congenital abnormalities.

The objective of the study was to check the human teratogenic potential of oral chlordiazepoxide treatment during pregnancy at the analysis of pairs of 22,865 cases with congenital abnormalities (CAs) and 38,151 matched healthy controls in the population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities (HCCSCA) between 1980 and 1996. Two hundred and one (0.9%) case mothers and 268 (0.7%) control mothers had chlordiazepoxide treatment during pregnancy, respectively. Our analysis showed higher odds ratio (OR) with 95% confidence interval (CI; 2.5, 1.0-6.0) for chlordiazepoxide use during the 2nd-3rd month of gestation in the group of congenital cardiovascular malformations. However, this association was found when exposure data were based mainly on maternal self-reported chlordiazepoxide treatments (80% in cases and 71% in controls). There was no increase in the rate of any specific congenital cardiovascular malformation type. In conclusion, therapeutic doses of chlordiazepoxide during pregnancy are unlikely to pose a substantial teratogenic risk to the human fetus, although a somewhat higher rate of congenital cardiovascular malformations cannot be excluded.