Taking folic acid before pregnancy, and through the first several weeks of pregnancy, may help reduce the risk of autism in children.
That's according to a new study published in the Journal of the American Medical Association.
Researchers in Norway looked at data from 85-thousand pregnancies.
They found women who took the supplement four weeks before pregnancy, and through the eighth week of pregnancy, were 39-percent less likely to have children with autism.
The study is the largest to date on the benefits of folic acid for autism prevention.
It marks one of the first tangible things a woman can do to reduce her risk of giving birth to a child with the disorder.
Some experts say more research needs to be done to confirm the link.