Objective: To study human teratogenic potential of oral oxytetracycline treatment during pregnancy.
Materials and methods: The pair analysis of cases with congenital abnormalities and matched healthy controls in the large population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996.
Results: Of 38,151 pregnant women who had babies without any defects in the study period (control group), 214 (0.6%) were treated with oral oxytetracycline. Of 22,865 pregnant women who had offspring with congenital abnormalities, 216 (0.9%) were treated with oxytetracycline (OR with 95%: 1.7, 1.4-2.0). Different approaches in the study showed a higher rate of medically documented oxytetracycline treatment in the second months of gestation in neural-tube defects (OR with 95%: 9.7, 2.0-47.1), cleft palate (17.2, 3.5-83.5) and multiple congenital abnormalities (12.9, 3.8-44.3) including mainly the combination of neural-tube defects and cardiovascular malformations.
Conclusion: Treatment with oxytetracycline during the second months of pregnancy presents a teratogenic risk to the fetus.