Pregnancy outcome after gestational exposure to mebendazole: a prospective controlled cohort study.

OBJECTIVE

Mebendazole is an anthelmintic that is commonly needed in women of reproductive age. Its use in pregnancy is a reason for concern for women and their health care providers. The purpose of this study was to examine the fetal safety of mebendazole.

STUDY

DESIGN

The Israeli Teratogen Information Service prospectively collected and followed 192 pregnancies exposed to mebendazole in pregnancy, 71.5% of whom had first-trimester exposure. Pregnancy outcome was compared with that of a matched control group, who were counseled for nonteratogenic exposure.

RESULTS

There was no increase in the rate of major malformations between the groups (5/150 pregnancies [3.3%; mebendazole] vs 3/175 pregnancies [1.7%; nonteratogenic control subjects]; P =.478). There was a higher rate of elective terminations of pregnancy in the exposed group compared with the control group (22/192 pregnancies [11.5%; mebendazole] vs 3/192 pregnancies [1.6% [nonteratogenic control subjects]; P =.000).

CONCLUSION

This study suggests that mebendazole does not represent a major teratogenic risk in humans when it is used in the doses that are used commonly for pinworm (Enterobius vermicularis) infestation.