Women who took folic acid and multivitamins before and during their pregnancy seem to reduce their risk of giving birth to a child with autism, according to the findings of a new study led by Stephen Z. Levine, Ph.D. at at the University of Haifa.
The researchers followed 45,300 Israeli children born between 2003 and 2007, until 2015; 1.3% were diagnosed with autism spectrum disorder (ASD).
Children with autism spectrum disorder (ASD) were compared with children who do not have it, to see whether the maternal use of the supplements could play a role. Health maintenance organization (HMO / kupat holim) data was reviewed, including pharmacy dispensation of folic acid and multivitamin prescriptions, to pregnant women.
The study, published online in JAMA Psychiatry on Jan. 3, found, that compared with women who had no exposure to supplements during pregnancy, women who took folic acid and/or multivitamins were at a reduced risk of 0.27 percent. (A relative risk of less than one percent suggests less risk.) Mothers who took folic acid and multivitamins before pregnancy had a reduced relative risk of 0.41 percent, compared with the mothers who did not.
Maternal exposure to folic acid and multivitamin supplements two years before pregnancy was associated with a reduced risk of ASD in offspring. The risk of ASD associated with maternal vitamin exposure was similar before and during pregnancy. The study could not determine whether this difference was due to the vitamin, or to unmeasured confounding by other conditions such a preterm birth or lifestyle factions, the researchers said.
The association between the use of multivitamin supplements and the risk of ASD was similar in male and female offspring. However, the analysis for female offspring had low power due to the small sample size. Also, among children whose parents were diagnosed with a psychiatric disorder, folic acid supplementation to the mother did not provide the same protection against ASD to the developing fetus, according to the study.
The researchers said there were several cautionary notes that needed to be made in drawing conclusions from this study: “Our study had a limited sample size and lacked the ability to conduct a sibling control analysis.” In addition, the underlying reason for the supplement dispensation was unknown as well, and some mothers may have used over-the-counter supplements that were not prescribed by the health care professional, leading to possible skewed data in the study.
Nevertheless, all that having been said, the researchers still maintain, “Reduced risk of ASD in offspring is a consideration for public health policy that may be realized by extended use of [folic acid] and multivitamin supplements during pregnancy.”
The study is called: “Association of Maternal Use of Folic Acid and Multivitamin Supplements in the Periods Before and During Pregnancy With the Risk of Autism Spectrum Disorder in Offspring”
JAMA Psychiatry. Published online January 3, 2018. doi:10.1001/jamapsychiatry.2017.4050