A large Norwegian study provides strong evidence that women who take prenatal vitamins containing folic acid, in the weeks before and after conception, reduce the risk that a future child will develop severe language delays—defined as speaking one word or less at age 3. The study, published Oct. 12 in the Journal of the American Medical Association, comes on the heels of a recent American study that found a significantly reduced risk of autism among children born to mothers who took prenatal vitamins before conceiving.
The senior author of the study was Ezra Susser, M.D., Dr.PH., professor of psychiatry and epidemiology at Columbia University’s Mailman School of Public Health and a member of Autism Speaks’ scientific advisory committee. The lead author was Christine Roth, M.Sc., Clin.Psy.D., of the Norwegian Institute of Public Health.
The investigators analyzed pregnancy questionnaires completed by nearly 109,000 pregnant women enrolled in the Norwegian Mother and Child Cohort Study. They compared the prevalence of severe language delay among 3-year-olds according to whether or not their mothers took supplements containing folic acid during the 4 weeks before and 8 weeks after conception. They found that a mother’s use of folic acid during this crucial period reduced her child’s risk of severe language delay from just under one percent (0.9%) to less than a half percent (0.4%). Unlike the United States, Norway does not require folic acid fortification of grain products.
For years, physicians have encouraged women to take prenatal vitamins with folic acid because its use during early pregnancy reduces the risk that a baby will be born with neural tube defects, another disorder of brain development, comments Dr. Susser. “It’s important not to make blanket recommendations based on this one study,” he adds. “At the same time, we’re seeing converging lines of evidence that the effect of folic acid deficiency may be a real clue to the underlying biology that leads to autism and related problems in language development.”