Babies born to women who take supplements of the B vitamin folic acid in early pregnancy are significantly less likely to develop autism, a developmental delay characterized by problems with communication and social interaction. The findings of a large Norwegian study reinforce those of other researchers that folic acid supplements are important to a healthy pregnancy.
Researchers at the Norwegian Institute of Public Health looked at health data on more than 85,000 children born between 2002 and 2008. The study asked the mothers to describe their food intake and all dietary supplements they took before and during their pregnancies. After the babies were born, investigators followed up with the children through the end of March 2012, looking to see how many developed a form of autism.
Research leader Pål Surén and colleagues compared pregnant women who took folic acid supplements to those who did not. “The women who took folic acid supplements in early pregnancy had a substantial reduction in risk of having a child with autism. The reduction was 40 percent,” explained Surén
Surén says four weeks before and eight weeks after conception appeared to be the critical time for folic acid supplementation to reduce the risk of autism. Investigators found no beneficial effects of folic acid later in pregnancy. They also found no connection between childhood autism and the use of other supplements during pregnancy, and no correlation with maternal intake of folate, the naturally-occuring form of folic acid, through foods.
The researchers report a total of 270 children were diagnosed with autism spectrum disorders, including 114 with autism and 56 with the milder Asperger’s syndrome.
Autism disorders range from Asperger’s, marked by social awkwardness, to severe involvement in which children are unable to communicate with the outside world. The cause of the syndrome is not known, although several genes have been implicated.
Folic acid has positively been linked to development of a protective covering called the neural tube in a fetus. Mothers deficient in folic acid are at risk of giving birth to infants with physical defects in which a portion of their spinal cords or brains are exposed because the neural tube does not fuse completely. This causes a crippling condition called spina bifida.
Ezra Susser, a co-author of the folic acid study, is with the Mailman School of Public Health at Columbia University in New York. “These supplements are already recommended for other reasons. So this increases the reasons why we should recommend them,” Susser added.
Dark leafy green vegetables, asparagus, broccoli and citrus fruit are rich sources of folate, the natural form of folic acid. But pregnant women can ensure they are getting enough to support their baby's neurological development by taking a supplement.
The study linking folic acid supplements with a reduced risk of autism is published in The Journal of the American Medical Association.