Antiepileptic Drugs, Weight Loss, and Pregnancy

Diane J. Angelini, EdD, CNM, FACNM, FAAN, NEA-BC

Maternal use of topiramate or zonisamide during pregnancy was associated with lower fetal birth weight and shorter fetal length.

In addition to its approved use for management of seizures and migraine headaches, topiramate is used off-label for weight loss. In an analysis of data from 2026 enrollees in the North American Antiepileptic Drug Pregnancy Registry and 457 pregnant women without epilepsy, investigators assessed the effects on fetal growth of in utero exposure to topiramate or zonisamide (another antiepileptic drug that causes weight loss). Outcomes in neonates of women using these two drugs were compared to outcomes in neonates of women using lamotrigine (a weight-neutral antiepileptic drug) and of nonexposed women.

Mean birth weight was 3458 gm in the unexposed group, 3402 gm in the lamotrigine group, 3200 in the zonisamide group, and 3181 gm in the topiramate group. Infants prenatally exposed to zonisamide or topiramate had mean shorter birth length of 1 cm (P<0.01 for both comparisons). Prevalence of small-for-gestational-age (SGA) infants was 6.8% in the lamotrigine group, 12.2% in the zonisamide group, and 17.9% in the topiramate group.

Citation(s):

Hernández-Díaz S et al. Association between topiramate and zonisamide use during pregnancy and low birth weight. Obstet Gynecol 2014 Jan; 123:21.