Risk of autism is significantly increased with prenatal exposure to valproate

Jakob Christensen, PhD, from Aarhus University Hospital in Denmark, and colleagues examined whether prenatal exposure to valproate correlates with the risk of autism in offspring in a population-base study involving 655,615 children born from 1996 through 2006 in Denmark.

Of the cohort, 5,437 were identified with autism spectrum disorder, including 2,067 with childhood autism. After 14 years of follow-up, the researchers found that the estimated absolute risk of autism spectrum disorder was 1.53%, and that of childhood autism was 0.48%. The absolute risks for the 508 children exposed to valproate were 4.42% for autism spectrum disorder (adjusted hazard ratio [aHR], 2.9) and 2.50% for childhood autism (aHR, 5.2). On restriction of the cohort to the 6,584 children born to women with epilepsy, the absolute risk of autism spectrum disorder was 2.44% for those not exposed to valproate (6,152 children) versus 4.15% for those exposed to valproate (432 children; aHR, 1.7); for childhood autism, the corresponding risks were 1.02% and 2.95% (aHR, 2.9).

“Maternal use of valproate during pregnancy was associated with a significantly increased risk of autism in the offspring, even after adjusting for parental psychiatric disease and epilepsy,” the authors write. “For women of childbearing potential who use antiepileptic medications, these findings must be balanced against the treatment benefits for women who require valproate for epilepsy control.”

One author disclosed financial ties to the pharmaceutical industry.

To read the JAMA abstract, click here.