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Folic acid, multivitamin use before, during pregnancy may lower autism risk

Study findings show that maternal use of folic acid and multivitamin supplements before and during pregnancy was associated with a lower risk of having a child with autism spectrum disorder, compared with children of mothers who were not exposed to these supplements.

“[Folic acid] and multivitamin supplements are routinely recommended to pregnant women,” Stephen Z. Levine, PhD, from the department of community mental health at the University of Haifa in Israel, and colleagues wrote in JAMA Psychiatry. “Epidemiologic studies report inconsistent associations between maternal supplementation with multivitamins or [folic acid] before and during pregnancy and the risk of ASD in offspring.”

The unclear association between maternal use of folic acid and multivitamin supplements before and during pregnancy and the risk of ASD in their children prompted researchers to examine this relationship in a case-controlled study of 45,300 Israeli children born from Jan. 1, 2003, to Dec. 31, 2007. They followed this cohort from birth to Jan. 26, 2015, to determine the risk for ASD. Maternal exposures included folic acid (vitamin B9), multivitamin supplements (vitamins A, B, C and D) and any combination of the two taken in the periods before and during pregnancy.

In total, 572 children were diagnosed with ASD. Maternal use of folic acid and/or multivitamin supplements before (RR = 0.39; 95% CI, 0.3-0.5) and during (RR = 0.27; 95% CI, 0.22-0.33) pregnancy was significantly associated with a reduced risk for ASD compared with no exposure. Adjusted risk ratios for ASD in children of mothers exposed to folic acid vs. those unexposed were 0.56 (95% CI, 0.47-0.83) for exposure before pregnancy, and 0.32 (95% CI, 0.26-0.41) for exposure during pregnancy. Adjusted risk ratios for ASD in offspring of mothers who took multivitamin supplements vs. those who did not were 0.36 (95% CI, 0.24-0.52) before pregnancy, and 0.35 (95% CI, 0.28-0.44) during pregnancy.

Among children born to parents with a psychiatric condition, however, folic acid supplementation before pregnancy did not reduce the risk for ASD. According to the researchers, this could be due to noncompliance, poor diet or higher rates of vitamin deficiency among people with psychiatric conditions.

“Maternal exposure to [folic acid] and multivitamin supplements before and during pregnancy is associated with a reduced risk of ASD in offspring compared with offspring of mothers without such exposure,” Levine and colleagues wrote. “Reduced risk of ASD in offspring is a consideration for public health policy that may be realized by extended use of [folic acid] and multivitamin supplements during pregnancy.” – by Savannah Demko

Disclosures: Levine reports receiving research support from Shire Pharmaceuticals. Please see the study for all other authors’ relevant financial disclosures.