Data from 241 younger siblings of children with autism indicated that the prevalence of autism spectrum disorder (ASD) was 14% when the mothers had taken prenatal vitamins in the first month of pregnancy, compared with 33% when mothers had not taken the supplements during that time.
“This study is the first to our knowledge to suggest that maternal prenatal vitamin intake during the first month of pregnancy may reduce ASD recurrence by half in younger siblings of children with ASD in high-risk families. These findings, if replicated, could have important public health implications for affected families,” wrote the study’s authors, led by Rebecca Schmidt, PhD, from University of California, Davis.
Highlighting the value of prenatal supplements
No dietary supplement should make claims relating to reducing the risk of autism, but the study’s findings do underscore “the importance of proper nutrition before and during pregnancy", said Andrea Wong, PhD, vice president, scientific & regulatory affairs for the Council for Responsible Nutrition (CRN). "These findings give further support for the role that proper nutrition, including supplementation with prenatal vitamins, has for healthy pregnancies and healthy babies.
Dr Wong added: “Folic acid, found in most prenatal vitamins in the U.S., is an essential nutrient proven to prevent birth defects, which is why the U.S. government along with other authoritative bodies on public health—the American College of Obstetricians and Gynecologists, the American Academy of Family Physicians, and the American Academy of Pediatrics—recommend women of childbearing age supplement with folic acid. Additional nutrients—iodine, choline, omega-3 fatty acids and iron—are also vital to the health and wellbeing of mother and baby, and can be obtained through supplementation if there are shortfalls in the diet.
“Research, like the findings released today, highlights the value of prenatal supplements. OB/GYNs are partners in good health, and CRN encourages women who are thinking of becoming pregnant to open up a dialogue with their doctors about their daily nutrient intake through both food and dietary supplements.”
The UC, Davis researchers assessed data from mothers and their children participating in the MARBLES (Markers of Autism Risk in Babies: Learning Early Signs) study. Mothers were interviewed about their prenatal vitamin use during pregnancy while the younger siblings at high risk for ASD completed a final clinical assessment within 6 months of their third birthday.
The results indicated that 96% of the mothers interviewed reported taking prenatal vitamins during pregnancy, but only 36% actually met the recommendations to take prenatal vitamin supplements in the 6 months before conception.
Children of mothers who took prenatal vitamins in the first month of pregnancy were found to have a lower prevalence of ASD, and also had statistically significantly higher cognitive scores.
“The association between prenatal vitamin use and reduced ASD risk could be owing to any of the many nutrients contained in these vitamins,” stated the researchers. “As suggested in previous studies, iron and especially folic acid are likely contributors given their high content in prenatal vitamins (compared with multivitamins, which were not associated with lower ASD risk), their importance in neurodevelopment, their depletion during pregnancy, and (especially for folic acid) the timing of their effect.
“Future work should examine the contributions of specific nutrients from supplements as well as food sources, overall diet quality, and biologic measurements of nutrient status, as well as investigate dose thresholds, interactions with genetic variants, and potential mechanisms,” they concluded.
Source: JAMA Psychiatry
Published online ahead of print, doi:10.1001/jamapsychiatry.2018.3901
“Association of Maternal Prenatal Vitamin Use With Risk for Autism Spectrum Disorder Recurrence in Young Siblings”
Authors: R.J. Schmidt, et al.