Pregnant women on topiramate for migraine/epilepsy require monitoring

The use of topiramate as monotherapy or as an adjunct to other treatment for epilepsy during pregnancy raises some concerns about the increased risk of congenital malformation, according to a report published in the July 22 issue of Neurology.

Stephen J. Hunt, of the Royal Group of Hospitals in Belfast, UK, and colleagues conducted a study of 203 pregnancies resulting in 178 live births among women who became pregnant while taking topiramate.

The investigators found that there were three major congenital malformations among the 70 women on topiramate monotherapy (4.8% of the total) and 13 cases among the 108 women on polytherapy (11.2%). The malformations included four oral clefts and four cases of hypospadias among 78 known live male births, two of which were classified as major malformations, the report indicates.

“While our results are preliminary, they are relevant not only in dealing with women with epilepsy of childbearing years. Topiramate is also licensed for use for migraine prophylaxis, an even more common condition which also occurs frequently in women of childbearing years. While the risks for adverse outcomes, including teratogenic endpoints, may differ between patient groups exposed to the same drug but used for different indications, the teratogenic potential of any agent is also likely determined by factors related to the structure and functional effects of the agent, the dose prescribed, and the timing of use,” the authors write.

Hunt S, Russell A, Smithson WH, et al. Topiramate in pregnancy. Preliminary experience from the UK Epilepsy and Pregnancy Register.

Neurology

. 2008;71:272-276