Published: February 12, 2013
Women taking folic acid, a B vitamin, before pregnancy were less likely to give birth to children with the most severe form of autism, a new study has found. Researchers in Norway and at Columbia University followed more than 85,170 Norwegian mothers who gave birth between 2002 and 2008, recording their prenatal diets and surveying them for six and a half years on average. Among their children, the researchers identified 270 with autism spectrum disorders, including 114 with autism disorder. The researchers found that the risk of having a child with autism disorder was reduced by 40 percent among women who had taken folic acid supplements during the critical developmental period from four weeks before conception and continuing eight weeks into the pregnancy. Still, the absolute risk that a child would have autism disorder was very low: 0.2 percent among women not taking folic acid, versus 0.1 percent among those who did. The study was published online on Tuesday in The Journal of the American Medical Association.