Medline ® Abstract for Reference 47

Pregnancies occurring in women who are epileptic are considered to be high risk. These women are at increased risk of seizures during pregnancy, labor, and delivery and of pregnancy complications and adverse pregnancy outcomes. Pregnancy alters the pharmacokinetics of anticonvulsant drugs, the levels of which decline as pregnancy advances. Not all drugs are altered in a similar manner, however. The rate of congenital malformations in infants of epileptic mothers is 2.4 times higher than in the general population. Malformations occur with all of the commonly used anticonvulsant drugs. The possible mechanisms of teratogenicity include folic acid antagonism, fetal tissue binding, and toxic effects of metabolic intermediates. Therapy with more than one drug increases the risk of congenital malformations. A unique hemorrhagic phenomenon in the infants of epileptic mothers has been reported and appears to be the result of a deficiency of vitamin K-dependent clotting factors. When taken by a pregnant woman, all antiepileptic drugs except valproic acid manifest themselves in breast milk, but only if the infant exhibits evidence of sedation should breastfeeding be discontinued. The dilemma for the physician treating the pregnant epileptic woman is to protect the mother from seizures and the fetus from unnecessary exposure to anticonvulsant medications.