Folate and antiseizure folate (vitamin B9) should be prescribed to all women of childbearing age who are taking antiseizure drugs. Patients taking valproate or carbamazepine should receive daily folic acid supplementation (4 mg/day) for one to three months prior to conception.

Women who are taking other antiseizure drugs should take the more standard lower dose of folic acid (0.4 to 0.8 mg per day).