Taking folic acid before pregnancy, and through the first several weeks of pregnancy, may help reduce the risk of autism for those children, according to a new study published Tuesday in the Journal of the American Medical Association (JAMA). Researchers in Norway looked at data from 85,000 pregnancies, and found that women who took the supplement four weeks before pregnancy, and through the eighth week of pregnancy, were 39% less likely to have children with autism. The Norwegian study is the largest to date on the benefits of folic acid for autism prevention, and marks one of the first tangible things a woman can do to reduce her risk of giving birth to a child with the disorder. "This is pretty exciting," said Alycia Halladay, senior director for environmental and clinical sciences for Autism Speaks, an autism advocacy group. "It actually supports the idea of actionable things women can do before they become pregnant, and right as conception happens." Experts have known for some time that taking folic acid can prevent neural tube birth defects like spina bifida in developing fetuses. American Congress of Obstetricians and Gynecologists (ACOG) guidelines call for all women of child-bearing age - not just those who plan to get pregnant - to take 400 micrograms of folic acid daily to prevent birth defects. The same dose appears to provide some benefit in preventing autism, according to the research. "This is another piece of evidence that supports the beneficial uses of folic acid during pregnancy," said Halladay, who was not connected with the study. The research "strongly suggests that taking folic acid prior to pregnancy may reduce the risk of autism in children," said Dr. Edward R.B. McCabe, medical director for the March of Dimes. The organization also recommends women of child-bearing age take 400 micrograms of folic acid daily before conceiving and 600 to 800 micrograms per day while pregnant. But some experts aren't quite ready to tout the benefits of folic acid too loudly, particularly for autism prevention. "It is possible that folic acid ... might provide protection against other neurodevelopmental disorders like autism," said Zachary Warren, director of the Treatment and Research Institute for Autism Spectrum Disorders at Vanderbilt University, who was also not involved in the study. "While the current study suggests such protection... the data really do not establish anything close to a causal connection." The Norwegian researchers do admit that more studies should be done to confirm the link. Warren says he wishes the solution were as simple as just taking folic acid. "Caring for individuals with autism and their families would be a whole lot easier if we had simple answers about cause and risk," he says. "The reality is, autism is a complex disorder and our best answers about causes and treatment are going to be complex as well." Despite the fact that a link between taking folic acid and reducing autism risk isn't fully proven, Halladay says there's no harm in taking the supplement, and women should be taking it anyway to prevent birth defects.