Prenatal folic acid supplementation shows protective effect against autism

Friday, March 15, 2013. The February 13, 2013 issue of the Journal of the American Medical Association reported the findings of researchers at the Norwegian Institute of Public Health of a protective benefit for supplementing with folic acid early in pregnancy against the risk of giving birth to a child with autism. The vitamin is routinely recommended to women who are pregnant or trying to conceive, to help prevent neural tube defects in their offspring.

The study included 85,176 children who were born between 2002 and 2008 who were followed through March, 2012. Mothers were recruited at 18 weeks of gestation and queried concerning their intake of vitamins, minerals and other supplements. Over the follow-up period, 114 children were diagnosed with autistic disorder, 56 with Asperger syndrome, and 100 with pervasive developmental disorder—not otherwise specified, all of which fall under the umbrella of autism spectrum disorder.

Mothers who consumed folic acid supplements during the period from four weeks prior to conception to their eighth week of pregnancy had a 40 percent lower risk of giving birth to a child diagnosed with autistic disorder in comparison with mothers who did not use the supplements. No association with Asperger syndrome or pervasive developmental disorder was noted, and no association was found for folic acid use during mid-pregnancy. "It appears that the crucial time interval is from four weeks before conception to eight weeks into pregnancy," stated lead researcher Pål Surén, MD, who is a doctoral fellow at the Norwegian Institute of Public Health.

"The findings show that a measure already used here in Norway, one which is simple, inexpensive and without any known side effects among pregnant women, can prevent autism," he remarked. "Previous studies we have carried out have shown that folic acid may have a similar effect on other developmental disorders as well."

"It will be a tremendous breakthrough if it turns out that folic acid also prevents other developmental disorders."

While over 70 percent of the mothers in the study reported supplementing with folic acid during their ninth through twelfth week of pregnancy, just one third were using the supplements before they conceived—a period during which an adequate supply of folic acid is important for the prevention of birth defects.

"We know that there is a genetic component to the body's ability to use folate, so it is possible that some mothers are more prone to folic acid deficiency than others," Dr Surén added.