MINNEAPOLIS (WCCO) – Researchers in Norway tracked 85,000 children and whether their mothers took a folic acid supplement.

In cases where women had taken one per month before pregnancy, and two months after, the children had a 39 percent lower risk of having autism.

Doctors say folic acid helps a baby’s brain develop during pregnancy.

Women can get enough by taking a prenatal vitamin.

“It is not in any way dangerous to the patient,” said Dr. Maria Costantini-Ferrand. “It is not costly … We would definitely recommend it.”

Folic acid has also been added to foods such as breakfast cereals since the 1990s.