Large Scandinavian Study Finds Many Antiseizure Medications Associated with Low Birth Weight in Infants

Results from the largest study to date on antiseizure medications and birth weight presented at the American Epilepsy Society Annual Meeting reveal that lamotrigine was not associated with either birth defects or low birth weight. Other agents studied, such as carbamazepine, oxcarbazepine, and topiramate, were associated with low birth weight. Low birth weight (defined as a weight < 5.5 lbs upon birth) is associated with a number of short- and long-term health problems, including respiratory, neurologic, and gastrointestinal issues. 

According to Dr. Jakob Christensen, lead author of the study: “Most concern has centered around which antiseizure mediations can cause birth defects and neurodevelopment issues in children, but clearly there have been gaps in our understanding of other risks of prenatal exposure to these medications, including birth weight.” Discontinuing antiseizure medications is often challenging for women who are pregnant owing to a number of factors, including withdrawal symptoms and seizure recurrence. 

In this study, researchers conducted a retrospective analysis of birth data from more than 4.49 million women in Scandinavian countries from 1996 through 2017, comparing birth weight in infants born to women taking antiseizure medications with the birth weight of infants born to women not taking such agents. Lamotrigine (taken by 8,760 women) was associated with higher infant birth weight whereas carbamazepine (3,420 women), oxcarbazepine (1,590 women), and topiramate (640 women) all were associated with low birth weight.