Teratogenic Risks of Antiepileptic Drugs

Elaine Wyllie, MD


November 16, 2000


How would you manage a patient with juvenile myoclonic epilepsy (JME) who wants to become pregnant? If a patient is already 6 weeks pregnant and taking valproic acid, and therapeutic abortion is not an option, what would you do? Is any data available from the Pregnancy Epilepsy Registry?

Leonor C. Lim, MD

Response from Elaine Wyllie, MD

Two independent scenarios can be considered:

If a woman taking valproate for JME wishes to become pregnant, then appropriate counseling would include consideration of a possible change to another antiepileptic drug that may carry a lower risk for teratogenicity (neural tube defect). Options include lamotrigine or topiramate.

The decision should be reached by the physician together with the patient after a detailed discussion of the potential risks and benefits of such a change. This same discussion would be pertinent to any woman of child-bearing age, because of the possibility of an unplanned pregnancy.

Supplementation with daily folate and a multivitamin is recommended for any woman of child-bearing age on valproate. Some epileptologists believe that folate supplementation is also appropriate for women of child-bearing age who are taking other antiepileptic drugs, because of the low but possible risk for neural tube defect with other older drugs and the unknown risk in new drugs. Dosage is controversial, but most epileptologists suggest 1-4 mg/day.

If a woman taking valproate for JME is already 6 or more weeks pregnant, then it is essentially too late to intercede in an effort to prevent the rare occurrence of spina bifida. In this scenario, it is appropriate to continue the valproate at doses that protect the patient against generalized tonic-clonic convulsions. If, in the case of myelomeningocele, abortion is not an option, then routine prenatal care and screening would be appropriate. Folate and vitamin supplementation remain important.

To my knowledge, no definitive data have yet been published from the Pregnancy Epilepsy Registry.


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