Objective: To study human teratogenic potential of oral nitrofurantoin treatment during pregnancy.
Materials and methods: Pair analysis of cases with congenital abnormalities and matched population controls in the population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996.
Results: Of 38,151 pregnant women who had newborn infants without any congenital abnormalities (population control group), 774 (3.4%); of 22,865 case pregnant women who had newborns or fetuses with congenital abnormalities, 1079 (2.8%) and of 812 pregnant women who had newborns or fetuses with Down's syndrome (patient controls), 23 (2.8%) pregnant women were treated with nitrofurantoin. The above differences between population controls and cases may be connected with recall bias, because the case-control pair analysis did not indicate a teratogenic potential of nitrofurantoin use during the second and the third months of gestation, i.e. in the critical period for major congenital abnormalities.
Conclusion: Treatment with nitrofurantoin during pregnancy does not present detectable teratogenic risk to the fetus.