The purpose of this study is to determine if antiepileptic drugs (AEDs) differ in their neurodevelopmental effects. Specifically, do the children of the women with epilepsy differ in their behavioral and cognitive development depending on which AED their mother takes during pregnancy?

This is a prospective investigation enrolling 285 to 380 women with epilepsy during the first two trimesters of their pregnancies. There are 25 clinical centers as well as the database center. The women will be taking one of the following AEDs: carbamazepine, phenytoin, valproate, or lamotrigine. Cognitive and behavioral testing of the child will be done up to the age of 6 years. The study does not change the woman's doctor and does not interfere with the care of the treating physician.

• Subject must be diagnosed with partial seizures and/or secondary generalization or primary generalized seizures (absence, atonic, myoclonic, and generalized tonic-clonic seizures)
• Subjects must be on either carbamazepine, lamotrigine, phenytoin, or valproate monotherapy.
• Mothers must not have a history of drug abuse (including alcohol) in the last year and have no sequelae of drug abuse.
• Mothers must be able to maintain an accurate seizure diary of major motor seizures
• Subjects must have an IQ greater than or equal to 70 points.
• Subjects must have a history of a negative RPR and HIV.
• Subjects must not have progressive cerebral disease or presence of other major medical illness
• Subjects must not have exposure to known teratogens during pregnancy, except AEDs.
• Subjects must not have poor compliance with prenatal care.
• Subjects must have adequate reading skills to perform the cognitive tests.

Mothers and their child(ren) who were exposed to one of the following monotherapies in utero- Lamotrigine, Carbamazepine, Phenytoin, or Valproate. Fathers of the children and a first degree materal relative of the mother are also invited to have IQ testing and medical history