While antiseizure medications are commonly prescribed during pregnancy, concerns remain about the long-term neurodevelopmental effects of in utero exposure to these drugs. That was the focus of a recent study led by Loreen Straub, MD MS, of the Division of Pharmacoepidemiology and Pharmacoeconomics at Brigham and Women’s Hospital.

Loreen Straub, MD, MS

Using over two decades of U.S. insurance claims data, Straub and team followed more than 23,000 children born to pregnant patients with epilepsy. The study compared children exposed to individual antiseizure medications during the second half of pregnancy—a critical period for fetal brain wiring—with children who were unexposed.

Outcomes encompassed a variety of disorders, including ADHD and autism spectrum disorder, with analyses adjusted for key maternal and clinical factors.

The findings reinforce long-standing concerns about valproate, which was associated with an increased risk of several neurodevelopmental disorders.

Zonisamide also showed signals of increased risk across multiple outcomes, though estimates were imprecise due to smaller sample sizes. In contrast, levetiracetam and phenytoin were not associated with increased neurodevelopmental risk.

Lamotrigine and topiramate were generally not linked to elevated risk, although both showed a potential association with intellectual disability based on small numbers. Carbamazepine and oxcarbazepine were associated with a modestly increased risk of ADHD and behavioral disorders.

Overall, the study highlights that neurodevelopmental risk varies by specific medication rather than antiseizure therapy as a whole. The authors emphasize the need for individualized treatment planning during pregnancy and continued surveillance of newer or less-studied medications.

Published in BMJ on March 11, 2026 | Read the paper: “Prenatal antiseizure drug exposure and risk of neurodevelopmental disorders in children: population based cohort study”

Summary reviewed by: Loreen Straub, MD MS, corresponding author