A population-based cohort study, the results of which were published online on the website of the Journal of the American Medical Association on April 24, has found that the children of women who used valproate during pregnancy had a higher risk of autism spectrum disorder and childhood autism compared with children of women who did not use valproate.
Valproate is indicated for the treatment of epilepsy, manic episodes associated with bipolar disorder, and prophylaxis of migraine headaches.
Researchers in Denmark conducted a population-based study of all children born alive in Denmark from 1996 to 2006. National registers were used to identify children exposed to valproate during pregnancy and diagnosed with autism spectrum disorders (childhood autism [autistic disorder], Asperger syndrome, atypical autism, and other or unspecified pervasive developmental disorders).
The researchers analyzed the risks associated with all autism spectrum disorders as well as childhood autism. Children were followed up from birth until the day of autism spectrum disorder diagnosis, death, emigration, or December 31, 2010, whichever came first.
They found that the use of valproate during pregnancy was associated with an absolute risk of 4.42% (95% CI, 2.59%-7.46%) for autism spectrum disorder (adjusted HR, 2.9 [95% CI, 1.7-4.9]) and an absolute risk of 2.50% (95% CI, 1.30%-4.81%) for childhood autism (adjusted HR, 5.2 [95% CI, 2.7-10.0]).
They also found higher risks of autism spectrum disorder (adjusted HR, 2.2 [95% CI, 1.02-4.9]) and childhood autism (adjusted HR, 5.6 [95% CI, 1.7-18.1]) among children of women who used valproate during pregnancy compared with children of women who were previous users of valproate but who stopped at least 30 days before conception.