Lower autism risk with folic acid supplements in pregnancy

Women who took folic acid supplements in early pregnancy almost halved the risk of having a child with autism. Beginning to take folic acid supplements later in pregnancy did not reduce the risk. This is shown in new findings from the ABC Study and Norwegian Mother and Child Cohort Study published in the Journal of The American Medical Association (JAMA).

Women who took folic acid supplements from four weeks before conception to eight weeks into pregnancy had a 40 per cent lower risk of giving birth to children with childhood autism (classic autism). Use of folic acid supplements midway through pregnancy (week 22) had no effect.

The findings only apply to a lower risk of childhood autism, the most severe form of autism. The results show no reduction in the risk of atypical or unspecific autism. The study also investigated the prevalence of Asperger syndrome, but the number of examined children was too low to give a reliable result.

Food and other supplements did not reduce risk
The researchers found no connection between childhood autism and intake of other supplements during pregnancy. They also found no correlation with maternal intake of folate through food.

"It appears that the reduced risk of childhood autism only reflects folic acid supplements, not food or other supplements, and that the crucial time interval is from four weeks before conception to eight weeks into pregnancy," says Dr Pa*l Sure'n, primary author of the paper and researcher at the Norwegian Institute of Public Health.

Clear results that pave the way for further research

The results show an association between the use of folic acid supplements in the mother during pregnancy and a reduced risk of childhood autism.

Facts:

Folic acid is a B vitamin that is essential for the construction and repair of DNA molecules, the genetic material which controls all body cells.
Folate is the naturally occurring form of folic acid and is found in leafy vegetables, peas, lentils, beans, eggs, yeast and liver.
For most pregnant women, folic acid supplements are required to reach the recommended levels of folate in the blood.
Some countries add folic acid to flour, so that the entire population receives a supplement, but this is not done in Norway.
Studies from other countries show that many pregnant women consume less dietary folate than is necessary to prevent neural tube defects.

"The study does not prove that folic acid supplements can prevent childhood autism. However, the findings are so apparent that they constitute a good argument to further examine possible causal mechanisms. It should also be ascertained whether folic acid is associated with a reduced risk of other brain disorders in children," says Sure'n.