Approximately 50% of women with epilepsy have no change in the frequency of their seizures during pregnancy, 40% to 45% have more frequent seizures, and 5% to 10% have fewer.
All patients treated with anticonvulsants who desire pregnancy should be carefully evaluated regarding the accuracy of the diagnosis of epilepsy and the continuing need for anticonvulsant therapy. In patients who have been seizure-free for 2 years or more, preconception anticonvulsant drug withdrawal may be considered. The major anticonvulsant drugs - phenytoin, phenobarbital, valproic acid, and carbamezapine - are teratogenic. The incidence of fetal malformations is correlated with the number of medications taken and with dosage. Patients should be advised, however, that the risk of poor fetal outcome is also high for women who experience grand mal seizures during pregnancy.
To maintain therapeutic concentrations of phenytoin and phenobarbital throughout pregnancy, it is usually necessary to increase the dosage as gestation advances. Patients receiving anticonvulsants should have serum drug concentrations measured at least monthly. Adequate folate supplementation must be provided. Dosages of anticonvulsants need to be decreased within 1 week after delivery to avoid toxicity. Breast-feeding is not absolutely contraindicated, but infants must be closely monitored for side effects from the medications.
The effect of pregnancy on the course of multiple sclerosis has been variable. Several studies have demonstrated that the number and severity of relapses diminish during pregnancy, particularly during the third trimester. In the past it has been suggested that exacerbations should be anticipated after delivery. More recent reports have not substantiated this concern.
Acute attacks are best managed with bed rest. The use of corticosteroids for severe attacks is advocated by some neurologists, but the efficacy of steroids for multiple sclerosis remains controversial.
Revision date: July 4, 2011
Last revised: by David A. Scott, M.D.