Teratogenic potential of vaginal metronidazole treatment during pregnancy

Abstract

Objective To study the human teratogenic potential of vaginal metronidazole treatment during pregnancy. Design and setting The analysis of cases with different congenital abnormalities and their matched controls in the population-based data set of the large Hungarian Case-Control Surveillance of Congenital Abnormalities (HCCSCA), 1980–1996. Study participants Pregnant women (38,151) who had newborn infants without any congenital abnormalities (control group), 22,843 pregnant women who had newborn infants or fetuses with congenital abnormalities. Main outcome measures Twenty-two congenital abnormality groups. Results The prevalence of vaginal metronidazole treatment during pregnancy was 1.7% in the case group (388 pregnant women), while it was 1.5% in the control group (570 pregnant women) [crude prevalence odds ratio (POR) with 95% confidence interval (CI): 1.1, 1.0–1.3]. Comparisons of cases and their matched controls showed an association between vaginal metronidazole treatment during the second and third months of gestation and congenital hydrocephalus (adjusted POR with 95% CI: 10.7, 1.1–104.5), however, based only on five cases. The evaluation of medically recorded metronidazole treatment did not confirm this association. Conclusion Our finding can only be regarded as a signal for the possible association between vaginal treatment with metronidazole during pregnancy and congenital hydrocephalus.