Use of antiseizure drugs with known or uncertain risks during pregnancy continues

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MINNEAPOLIS — Despite evidence of the risk of malformations at birth, or birth defects, use of some antiseizure drugs during pregnancy has persisted, according to a study published on July 23, 2025, in Neurology®, the medical journal of the American Academy of Neurology. Use has also increased for drugs where there is not enough evidence to know if they are safe during pregnancy. People with a low level of resources had a disproportionately higher use of these drugs than people with a higher level of resources.

“These medications can be used for epilepsy, mood disorders, chronic pain and migraine, which often occur at young ages, and sometimes people are taking them before they realize that they are pregnant,” said study author Rosemary Dray-Spira, MD, PhD, of the French National Agency for the Safety of Medicines and Health Products in Saint-Denis. “The good news is that use of the drugs with the greatest risks has decreased, and use of the safest drugs has increased, but we are concerned to still see use during pregnancy of some drugs with known risks and new drugs with uncertain risk.”

The study looked at comprehensive data from a French national pregnancy registry for information on all pregnancies with exposure to at least one antiseizure medication from 2013 to 2021. The drugs were placed in three safety categories. The safest: lamotrigine and levetiracetam; those with uncertain risk, including pregabalin, gabapentin and newer drugs such as lacosamide and zonisamide; and those with known risks, including valproic acid, valpromide, carbamazepine and topiramate.

A total of 55,801 pregnancies were exposed to at least one antiseizure medication.

Those exposed to the safest drugs increased by 30% over the study.

Those exposed to valproic acid and valpromide dramatically decreased due to decreasing numbers of exposed pregnancies (down by more than 80%), increased termination rates of exposed pregnancies and among those that ended in childbirth, decreasing numbers of people having more than one 30-day prescription filled for the drug or sustained exposure to the drug throughout pregnancy.

Exposure to carbamazepine and topiramate barely decreased over the study period.

Pregabalin and gabapentin became widely used during pregnancy during this time, resulting in more newborns exposed (28% increase) and for pregabalin increasingly with multiple prescriptions and sustained exposure throughout pregnancy.

Exposure to newer drugs with uncertain risks also increased over time.

Researchers also divided the participants into three groups based on level of resources, which was defined by salary and use of a program that helps cover health care costs that are not covered by basic health insurance for people with a low income.

While mothers with low resources accounted for nearly one-fifth of pregnancies exposed to drugs with either known risks or uncertain risks (18% and 19%, respectively), this proportion was lower among pregnancies exposed to the safest drugs (14%).

“These disparities could be due to various factors, including more frequent unplanned pregnancies and suboptimal care before conception or during pregnancy for people who are socioeconomically disadvantaged,” Dray-Spira said. “More work is needed to further reduce exposure during pregnancy to these drugs, especially among the most socially disadvantaged populations.”

A limitation of the study was that information about exposure to the drugs was based on claims, not on actual use of the drugs.

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