Children born to mothers who took the anti-seizure drug valproate were five times more likely to be born with autism than those whose mothers didn't take the medication, a Danish study found.
The epilepsy drug was also tied to a threefold increase of autism spectrum disorder, which includes Asperger syndrome and other developmental disorders, according to research published today in the Journal of the American Medical Association.
The findings show conclusively that valproate should be avoided and other treatments used instead to control seizures in women of childbearing age to reduce risk of autism in their unborn children, said Kimford Meador, a neurologist who wrote an accompanying editorial.
If not, only the lowest dose of the drug should be given. Previous research has linked valproate's use during pregnancy to heart defects, spina bifida, cleft palates and cognitive problems including lower intelligence scores.
"This is an important risk factor and one that can be avoided or at least the risk reduced in women who don't need to take this and can take another drug," Meador, a professor of neurology at Emory University in Atlanta, said Monday in a telephone interview. "This is the strongest evidence to date that there is a link between fetal exposure and childhood autism or autism spectrum disorder."
Other Uses AbbVie Inc., based in North Chicago, Ill., sells valproate under the brand name Depakote. The drug is approved by the U.S. Food and Drug Administration to treat seizures, prevent migraine headaches and treat manic episodes associated with bipolar disorder. It is also used by doctors off-label for other conditions, particularly psychiatric disorders, according to the FDA website.
The agency in 2011 warned women of childbearing age that valproate was associated with lower cognitive scores in children whose mothers took the drug during pregnancy. It had previously warned that the medicine was linked to birth defects.
Christopher Stodgell, an associate professor in the Department of Obstetrics and Gynecology at the University of Rochester Medical Center in New York, who wasn't an author on 's paper but is studying how valproate causes autism, said the drug may turn on genes in the body too much, not at all or at the wrong time that could ultimately change the way the nervous system develops. He said though it's too soon to know for sure.