A new study suggests taking multivitamins with folic acid before and during pregnancy may lower autism risks.

prenatal folic acid
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If you needed more reasons to be sure to take your prenatal vitamin, here's another: Getting enough folic acid may help to prevent autism spectrum disorder (ASD) in your child. A recent study in The Journal of the American Medical Association Psychiatry found a link between the use of folic acid and multivitamin supplements by women before and during pregnancy, and a lower likelihood of ASD in their children.

The link between folic acid and the brain

The study followed over 45,000 Israeli children born between 2003 and 2007 from birth to 2015. At the end of the study period, 572 children had received an autism diagnosis. After looking at which moms took folic acid and/or multivitamins during pregnancy, the researchers found those who did had a 73 percent lower chance of their child having ASD. Taking the supplements before pregnancy was also effective in reducing risk.

Until now, the connection between autism and folic acid has been unclear. "The association of maternal use of folic acid and multivitamin supplements before and during pregnancy with the risk of autism spectrum disorders in offspring is a topic of debate," study author Stephen Z Levine, PhD, of the University of Haifa in Israel, tells Parents.com. "Few studies have examined the association. Our results provide evidence in favor of a risk reduction before and during pregnancy, thereby swaying the debate."

"The results of this study are quite significant," Mary Jane Minkin, MD, Clinical Professor of Obstetrics & Gynecology at Yale University, who was not involved in the study, tells Parents.com. "This recent Israeli paper confirms some previous data showing the reduction in risk of developing autism with folic acid supplementation."

Doctors already know folic acid influences baby's brain, because a lack of the nutrient leads to neural tube defects that affect the brain and spinal cord. "We have known for over 25 years that supplementation with folic acid before the time of conception significantly reduces the chance of a baby being born with congenital abnormalities such as spina bifida," Dr. Minkin says. "Although we don't know the exact mechanism of why the development of autism could be affected by the presence of folic acid, we do know that folic acid clearly somehow affects neurological development."

This study only provides a link—not cause and effect—but it does seem plausible that folic acid could affect the chances of ASD. This research, though, doesn't explain exactly how. "The vitamin may have resulted in epigenetic modifications, which are alterations in gene expression," Dr. Levine says. "However, other factors could also play a role, such as preterm birth or lifestyle factors." Because other things may have affected the results, the authors urge caution in interpreting the study.

Avoid casting blame on moms

The study also shouldn't be used to shame mothers of children with ASD for what they did or didn't do before or during their pregnancies. "Mothers of children with autism spectrum disorders should not be blamed or stigmatized," Dr. Levine says. "Autism has complex multiple genetic and environmental causes, so it follows that many mothers who did use adequate vitamins before and during pregnancy would have a child who developed autism." Dr. Minkin agrees, stressing that moms of kids with autism shouldn't feel guilt over their vitamin use. "Of course, one should never blame oneself for not taking folic acid," Dr. Minkin says.

Still, the results of the study shed light on the importance of taking folic acid if you're pregnant—and even before. "Given that women don't know they are pregnant in general until they miss a period, significant developments are happening in the uterus prior to that missed period," Dr. Minkin says. "Obstetricians and gynecologists in this country routinely recommend that any woman who is trying to conceive take a prenatal vitamin with folic acid, and not to wait until she knows she is pregnant."

And actually, as nearly half of pregnancies are unplanned, you should consider a multivitamin with folic acid even if you're not currently trying to have a baby. Dr. Levine points out the CDC's recommendation that "any women who can get pregnant should consume 400 micrograms of folic acid daily."