HealthDay News — Taking folic acid supplements around the time of conception may reduce the risk for having children with autistic disorder, results of an observational study suggest.

Women who took folic acid from four weeks prior to and eight weeks after conception were significantly less likely to have a child later diagnosed with an autistic disorder than those who did not (0.1% vs. 0.21%; OR=0.61; 95% CI: 0.41 to 0.90), Pål Surén, MD, MPH, from the Norwegian Institute of Public Health in Oslo, and colleagues, reported in Journal of the American Medical Association.

This finding represents a 39% lower odds of autistic disorder in children of folic acid users. Similar associations were not observed for Asperger syndrome or pervasive developmental disorder-not otherwise specified (PDD-NOS), the researchers noted.

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They added that the study did not establish a cause and effect relationship between folic acid intake and autistic disorder, “but provides a rationale for replicating the analyses in other study samples and further investigating genetic factors and other biological mechanisms that may explain the inverse association.”

Previous studies have shown an association between prenatal folic acid use and lower risks of severe language delays and autism spectrum disorders (ASDs). To further explore the relationship, Surén and colleagues analyzed data from 85,176 children born between 2002 and 2008 who participated in the Norwegian Mother and Child Cohort Study and a substudy called the Autism Birth Cohort study.

Child age ranged from 3.3 to 10.2 years (mean 6.4 years) at follow-up for ASD diagnosis. As of March 31, 2012, the researchers determined that 270 children had been diagnosed with an autism spectrum disorder — 114 with autistic disorder, 56 with Asperger syndrome, and 100 with PDD-NOS.

Current Norwegian prenatal health guidelines recommend all women attempting to become pregnant take 400 µg of folic acid daily from one month before conception through the first trimester. At the time of the study, no foods in Norway were fortified with folic acid. A total of 71.7% of study participants reported using folic acid around the time of conception.

The risk of being diagnosed with an autistic disorder was significantly lower for children whose mothers had taken folic acid. This was the only disease significantly associated with with maternal folic acid supplementation after adjusting for year of birth, parity, maternal education level, illness and medication use.

“The potential for a nutritional supplement to reduce the risk of autistic disorder is provocative and should be confirmed in other populations,” Robert Berry, MD, MPHTM, of the CDC’s Division of Birth Defects and Developmental Disorders in Atlanta, wrote in an accompanying editorial.


  1. Surén P et al. JAMA 2013; 309: 570-577.
  2. Berry R et al. JAMA 2013; 309: 611-613.