Autism risk and prenatal vitamins: Here’s what UCD researchers found
The risk and severity of autism decreases for high-risk siblings of children with autism if moms take prenatal vitamins in their first month of pregnancy, according to research released Wednesday by the MIND Institute at the University of California, Davis.
It’s the first time research has shown that families with a high risk for autism in successive children also can benefit from the mother taking prenatal vitamin supplements near conception, UCD researchers said, something that they already had found true for first pregnancies among women in the general population.
“This study is looking at high-risk families where there’s likely a larger genetic contribution to the autism diagnosis, so we weren’t sure they would have the same sort of risk reduction” as the general population, MIND Institute researcher Rebecca J. Schmidt said. “If it’s mostly genetics, then you would think that maybe something like this wouldn’t help as much, but it turns out that, at least in our study population, it looks like there was again this association with reduced risk.”
The latest MIND Institute findings, released Wednesday in the medical journal JAMA Psychiatry, led Schmidt to say that it’s probably not a bad idea for any woman of childbearing age who is sexually active but isn’t protecting against pregnancy to take a prescribed prenatal multivitamin that includes folic acid.
Schmidt said that her team followed 241 families affected by autism for this study. The families were at greater risk for later siblings to inherit the genetic trait for autism, but when women started taking prenatal vitamins in the critical early stages of a pregnancy, the risk of autism dropped by about half for later siblings.
“This is about protection against recurrence of ASD in high-risk younger siblings of children with autism,” said Schmidt, an assistant professor in the UC Davis Department of Public Health Sciences.
Not all the high-risk families in the study were planning a pregnancy, but they were not actively protecting against one, Schmidt said. Some moms were taking prenatal vitamins at conception while others were not.
Medical experts recommended that women start taking these supplements before getting pregnant, Schmidt said, and the UCD studies have shown the benefits. Children whose mothers did so were less likely to be diagnosed with autism spectrum disorder, had significantly lower autism symptom severity, and posted higher cognitive scores as they aged.
It appears to be crucial, Schmidt said, that the fetus have the right nutrients for development starting at conception, and it can take a few months for women to build up stores of nutrients in their system. While folic acid has been shown to be crucial at that early stage of establishing neural pathways, Schmidt said that researchers do not yet know what other vitamins play as vital a role.
She urged women to seek prescription prenatal vitamins because over-the-counter supplements are not regulated by the U.S. Food and Drug Administration. It’s important, Schmidt said, that women know they’re getting what their bodies need.
One in every 59 children in the United States has been diagnosed with some form of autism spectrum disorder, UCD researchers said, and younger siblings of children with the disorder are about 13 times more likely to develop it than the general population. The risk of recurrence is nearly 1 in 5.
If the study results can be replicated, Schmidt said, it implies that genetic susceptibility could potentially be overcome by taking maternal prenatal multivitamins. Doctors recommend that women start taking prenatal vitamins before trying to conceive, but the UCD study found that only about 34 percent of women in the study had started them prior to conception. Virtually all the study participants, 96 percent, had taken prenatal multivitamins, including folic acid, prior to giving birth.
The study’s subjects included:
- Mothers who had a child with confirmed ASD and were planning a pregnancy or were pregnant with another child.
- Younger siblings at high risk for autism born between 2006 and 2015 and who received a diagnosis at age 3.
Schmidt said that some women who already had children with autism were not taking folic acid during their second pregnancies because of inaccurate online reports that it could cause autism.
“When we look at the data on an individual level, there’s really not evidence for that. If anything, it seems to be quite helpful,” Schmidt said. “It was important that we get this message out, that these high-risk families should not be avoiding folic acid supplements or prenatal vitamins in general,”
The latest UCD research was funded by the Allen Foundation, the MIND Institute, the U.S. Environmental Protection Agency and the National Institutes of Health.