A population-based case-control teratological study of oral nystatin treatment during pregnancy.

The aim of the study was to investigate the teratogenicity of oral nystatin treatment during pregnancy in the population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities between 1980 and 1996. In total, 38,151 pregnant women who delivered newborn infants without any defects (control group) and 22,843 pregnant women who had foetuses or newborns with congenital abnormalities (CA) (case group) were included in the study. 106 (0.5%) case and 143 (0.4%) control pregnant women were treated with oral nystatin (crude OR with 95% CI = 1.2, 1.0-1.6). A teratogenic potential of nystatin was seen in 1 CA-group (hypospadias) in 2 different approaches of the study (case-control and total control--CA groups comparison) during the critical period of this congenital abnormality. The conclusion of the study is that treatment with oral nystatin during pregnancy presents little teratogenic risk to the foetus, but the possible association between hypospadias and nystatin needs further study.