A case-control teratological study of vaginal natamycin treatment during pregnancy.

The aim of this study was to investigate the teratogenicity of vaginal natamycin treatment during pregnancy, because the data of human epidemiological studies have not been published. Pair analysis of cases with congenital abnormalities and matched healthy controls was carried out. The population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities between 1980 and 1996 included as total, 38,151 pregnant women who delivered newborn infants without any defects (control group) and 22,843 pregnant women who had fetuses or newborns with congenital abnormalities. 62 (0.27%) and 98 (0.26%) pregnant women were treated with the natamycin in the case and control groups, respectively (crude OR 1.1 with 95% CI: 0.8-1.5). A teratogenic potential of vaginal natamycin treatment during the second and third months of pregnancy, the critical period of most major congenital abnormalities, was not indicated in the case-control pair analysis (adjusted OR 0.9 with 95% CI: 0.4-1.8). A somewhat higher mean birth weight (72 g) was found in control newborn infants born to mothers with natamycin treatment compared with the data of control newborn infants without this treatment (adjusted P=0.01), though mean gestational age was shorter. The conclusion of this study is that the treatment with vaginal natamycin during pregnancy presents no detectable teratogenic risk to the fetus.