Reporting their findings in the Journal of The American Medical Association, European researchers say women who take folic acid supplements in early pregnancy can almost halve the risk of having a child with autism.
The Norwegian study involved children who were born in 2002-2008 and included a total of 85,176 children. The mothers had given detailed information about their diet and the use of supplements in early pregnancy. Children with autism diagnoses were identified through questionnaires, referrals from parents and health personnel and through links to the Norwegian Patient Register.
The findings showed that 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. The use of folic acid supplements midway through pregnancy (week 22) was found to have no effect.
The researchers found no connection between childhood autism and the intake of other supplements during pregnancy. Interestingly, 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 Pĺl Surén, lead author of the paper and researcher at the Norwegian Institute of Public Health.
Surén adds that the results support current recommendations for folic acid supplements during pregnancy and emphasize the importance of starting early - preferably before conception.
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Source: Norwegian Institute of Public Health