Course of pregnancy and fetal outcome following maternal exposure to carbamazepine and phenytoin: a prospective study.

This prospective study followed the pregnancy course of epileptic women at the Motherisk Program of The Hospital for Sick Children, Toronto. We compared fetal outcome of women treated with carbamazepine (CBZ), those treated with diphenylhydantoin (phenytoin, DPH), and a drug-free control group. Seizures were reported in 15 pregnancies; in a subgroup of 9 women without change in drug or schedule, an increase in seizure frequency was evident in 6, a decrease in 1, and no change in 2, regardless of the drug taken. Of 23 children exposed to CBZ in utero, one was born with a lumbar myelomeningocele and multiple congenital anomalies. Of 21 children exposed to DPH, there was one case of severe developmental delay and four with minor features of fetal hydantoin syndromes (FHS). The three groups did not differ in birth weights or gestational ages of the babies. Although much more experience is needed, as a result of this study and other similar reports, Motherisk now offers women treated with CBZ diagnostic tests to detect neural tube defects during the second trimester of pregnancy.