Pregnant women are encouraged to get plenty of folic acid in their diet or through vitamin supplements, to protect their babies against birth defects of the brain and spinal cord.But a new study suggests that excessive amounts of folate (vitamin B9) and vitamin B12 in a mother’s body might increase a baby’s risk of developing an autism spectrum disorder.
RELATED: Inducing Labor May Carry Autism Risk: The study also found that women who took folate and B12 supplements three to five times a week were less likely overall to have a child with autism, particularly when they’re taken during the first and second trimesters, Fallin said.The March of Dimes, the American College of Obstetricians and Gynecologists and other medical associations recommend that pregnant women consume folic acid to prevent neural tube defects, which happen in about 3,000 pregnancies each year in the United States. Spina bifida is the most common of this type of birth defect.And recent studies have also indicated that folate and vitamin B12 might protect a developing fetus against future autism, Fallin said.To investigate this effect, Fallin and her colleagues analyzed data from almost 1,400 mother-child pairs in the Boston Birth Cohort, a predominantly low-income minority population.
The researchers found that one in 10 of the women had what is considered an excess amount of folate, while 6 percent had an excess amount of vitamin B12.”We saw those women who had extremely high, much higher than the recommended amount, of folate or vitamin B12 were more likely to have children who later had a diagnosis of autism,” Fallin said.Fallin and her colleagues could not say from their data why certain women had excessive levels of folate or B12 in their systems around the time of delivery, although many said they took vitamin supplements during their pregnancy.It could be that some women are genetically predisposed to high levels of folate and B12 in their bodies, or they might be getting too much of the nutrient through diet or supplements, she said.Women should talk with their obstetrician about their diet and supplements, and how those might be affecting their blood levels of folate and B12, Fallin said.Dr. Paul Wang, senior vice president of medical research for Autism Speaks, agreed that “it’s just too early to say” what this study means, particularly because it hasn’t yet appeared in a peer-reviewed medical journal.