Birth defects after exposure to misoprostol in the first trimester of pregnancy: prospective follow-up study.

Misoprostol during the first trimester of pregnancy is associated with a specific malformative pattern (Moebius sequence and limb defects) whose incidence remains unknown. Data originate mostly from illegal use for abortion and are mainly retrospective. The present prospective controlled study analyses outcomes of first trimester misoprostol exposures after medical prescriptions. Malformation rate was higher among 236 pregnancies exposed before 12 gestational weeks (4%) than in 255 controls (1.8%), although not statistically significant (OR=2.2 [95% CI=0.6-7.7]). Three malformations (2%) in the exposed group were consistent with the misoprostol malformative pattern. This is the largest prospective study on first trimester misoprostol exposure and the first one relying on prescriptions. A trend toward a doubling of the overall rate of malformations was observed and for the first time an estimation of the incidence of misoprostol specific spectrum is proposed (2%). Brainstem injuries including severe trismus might be added to this specific pattern.