Risks of pregnancy in women with epilepsy.

Pregnant women with epilepsy are at increased risk of seizures and complications. An increase in seizure frequency is seen in 25-30% of pregnant women with epilepsy; the offspring of mothers who experienced seizures during pregnancy are at a 2.5 times higher risk for seizures later in life. One of the main reasons for the increase in seizures during pregnancy is a decline in plasma concentrations of antiepileptic drug (AED) that occurs as pregnancy progresses, largely as a result of marked alterations in plasma protein binding. It is well known that epilepsy represents a risk for a variety of adverse pregnancy outcomes or malformations, especially in polytherapy. The adverse outcomes range from dysmorphic features to hemorrhagic disorders resulting from a deficiency of vitamin K-dependent clotting factors or to spina bifida. Folic acid supplements appear to reduce the risk of spina bifida. A strong genetic link seems to exist for many of the malformations that occur, and more research is required in this field. In the meantime, there are interventions that clinicians can already make to reduce the risk of adverse outcomes, such as seizure control without toxicity, monotherapy, and preconceptual use of vitamins with folate.