This patient should begin taking levetiracetam and be weaned off valproic acid. She has juvenile myoclonic epilepsy, which responds particularly well to valproic acid. However, valproic acid should be avoided whenever possible in women of childbearing age because this antiepileptic drug (AED) is associated with a significantly elevated risk (6%-16%) of major congenital malformations, which is much higher than that of other AEDs. In utero exposure to valproic acid also is associated with a 7- to 10-point decrease in intelligence quotient (IQ) on average and an increased risk for autism and autism spectrum disorders in the offspring. Therefore, whenever possible, a trial of another suitable AED should be attempted before pregnancy. This patient should be advised to switch to levetiracetam, which has shown a relatively low risk of birth defects when used in pregnancy. Lamotrigine is another reasonable option, but starting lamotrigine while a patient is still taking valproic acid carries an increased risk of Stevens-Johnson syndrome. If she does not respond to levetiracetam or the drug has adverse effects, lamotrigine, with or without levetiracetam, would be another reasonable choice. If a woman does not respond to treatment with other suitable medications and needs to remain on valproic acid, the dose should be adjusted during pregnancy to the minimum therapeutic dose required. Women should be counseled to use contraception during any period of drug transition from valproic acid because of the drug's significantly increased teratogenic risk.

Carbamazepine is not a good choice for this patient because it is a narrow-spectrum drug used to treat focal epilepsies. Carbamazepine potentially can exacerbate generalized epilepsies, such as juvenile myoclonic epilepsy, and should be avoided in this patient.

Topiramate can be used to treat juvenile myoclonic epilepsy. However, early data suggest that this drug is associated with a moderately increased risk of major congenital abnormalities, particularly cleft lip/cleft palate and small-for-gestational-age infants.

Stopping all AEDs can be considered in some women who have been seizure free for 2 or more years. However, it is rarely an option for patients with juvenile myoclonic epilepsy. These patients typically need life-long AED treatment, and the risk of seizures during pregnancy typically outweighs the potential complications of AED therapy, when selected carefully. The fact that this patient had a seizure after stopping her AED strongly suggests that she should stay on her medication during pregnancy.