Home > Science > Early maternal prenatal vitamin intake associated with reduced risk for autism

Early maternal prenatal vitamin intake associated with reduced risk for autism

This post is by Guest Blogger Rebecca Schmidt, Ph.D., Assistant Professor, Department of Public Health Sciences, UC Davis and first author on the research described below.

UC Davis researchers conducted a study comparing children with autism to children without autism, all aged 24-60 months, to see whether their mothers differed in terms of taking prenatal vitamin supplements before and during pregnancy. Combined effects of maternal vitamin intake and genotypes affecting a key metabolic pathway known as one-carbon metabolism were also examined.

In this retrospective study, mothers of  children with autism were significantly less likely than those of typically developing children to report having taken prenatal vitamins during the three months before and the first month of pregnancy. Prenatal supplement use was similar across the other months of pregnancy. Maternal education and the child’s birth year were accounted for; however, because the mothers were asked about their vitamin use years after their pregnancy, and after their child’s developmental status was known, recall bias could have influenced the results.

The researchers postulate that folic acid, the synthetic form of folate or vitamin B9, and the other B vitamins in prenatal supplements, are probably protecting against deficits in early fetal brain development. Folate is known to be critical for proper neurodevelopment and studies have found that supplemental folic acid has the potential to prevent up to 70 percent of neural tube defects.

Interaction effects were also observed between periconceptional prenatal vitamin intake and maternal and child genotypes. When a mother did not report taking prenatal vitamins and she or her child had genotypes associated with less efficient folate-dependent one-carbon metabolism, the child was at much greater risk for autism. These findings demonstrate gene/environment interactions in autism.

Maternal genes involved in significant interaction effects included the well-studied methylenetetrahydrofolate reductase (MTHFR) folate metabolism gene and vitamin B6-dependent cystathionine-beta-synthase (CBS), which is an enzyme involved in metabolizing protein building-blocks that contain sulfur. The child’s catechol-O-methyltransferase (COMT) gene was associated with more than seven times the risk for autism when in combination with no maternal periconceptional prenatal vitamin intake, compared to children with other genotypes whose mothers did report periconceptional prenatal vitamin intake. The COMT enzyme, responsible for the degradation of the neurotransmitter dopamine and well-known for its association with schizophrenia, is active during early neurodevelopment. Structural and functional brain differences have been described across COMT genotypes, particularly in the hippocampus and prefrontal cortex, regions previously shown to be affected in individuals with autism.

These findings are the first to suggest a concrete step women can take that may reduce the risk of having a child with autism. Future research is warranted to replicate these findings and enhance understanding of potential mechanisms.


  1. Katie Wright
    May 26, 2011 at 11:09 pm

    Hasn’t every woman been told- for decades- to take a prenatal vitamin prior to trying to conceive and when an OBGYN confirms a pregnancy? That is what I was told and what I did. If only preventing autism were this simple!
    I gave birth to a healthy baby who suddenly became autistic at age 2. We really need more ASD research focusing on postnatal environmental factors.

    • Lisa
      May 27, 2011 at 3:15 pm

      I agree with Katie Wright, I took prenatal vitamins before and after conceiving my twins…I took the finest plant based DHA supplements as well as prenatal supplements with folic acid…both of my twins are HFA.

      • John HItchman
        May 29, 2011 at 7:19 pm

        Us also. My wife took prenatal vitamins, did not drink etc. Almost perfect pregnancy. Our daughter has PDD. She is 11 now. Funny, we stopped vaccines and she almost is never sick, maybe missed two days of school her entire life.

  2. Michele Williams
    May 27, 2011 at 4:41 pm

    I totally agree with this article. My 4 year old grandson shows signs of autism and as his mother and I looked back at all types of factors that could have contributed to this, we remembered that she didn’t take her prenatal vitamins with that pregnancy because they actually made her sick at the time. If only we had realized how important those could be.

    • sarah
      June 1, 2011 at 7:10 pm

      Dont read too much into it. Most women have taken the vitamins (me included) and my son still has autism….everyone has their theories, none have been correct yet…… It may be another decade before they figure out the how, when, and why’s of autism.

  3. May 28, 2011 at 11:05 am

    I took the vitamins as described, and my son has “classic” autism. As noted previously, women have been told to take these vitamins for quite some time (especially regarding Spina Bifida). So this doesn’t explain why the incidences of autism are skyrocketing. Doesn’t hurt to promote vitamin intake, but we can’t stop there!

  4. Robert Segura
    May 28, 2011 at 11:07 pm

    My wife Shirley took her Prenatal Vitamins every day and our son was Diagnosed two weeks after receiving 3 vaccine shots all at once. We need research on environmental factors & vaccines and how they effect certain genes.

    • elise baucum
      June 1, 2011 at 4:03 pm

      my daughter had 3 shots also and got autism
      regardless of vitamins and good birth

    • Maureen
      June 2, 2011 at 9:29 pm

      I agree with you Robert.

  5. beylis
    May 30, 2011 at 5:27 pm

    I totaly desagree with the article. I did start taking the Prenatal Vitamins even before to get pregnant and my son was diagnosed with Autism before he was turning 2 years old. I read another article that said that Autistics’ chinldren have differnt shape of head than children without Autism, and I think that it happened to my son in the delivery process when doctors took too much time to take him out.

    • Sarah
      June 1, 2011 at 5:26 pm

      It is really a mystery. My daughter was born VERY fast (only two hours of labor and 2 minutes of pushing). She also has autism.

  6. elise baucum
    June 1, 2011 at 3:51 pm

    I took prenatal vitamins and my beautifil
    daughter was diagnosed at age 2 after her mmr

  7. BreeAnn
    June 1, 2011 at 5:11 pm

    If genetics and enviornment are a factor in autism, then this story would not be true with everyone. I honestly do not belive there is one solid cause to autism. Each child with autism is different, and it makes sense to me that there would be different causes. I wonder if birth control pills factor into this equation at all.

    • Maureen
      June 2, 2011 at 8:33 pm

      I don’t think that birth control pills factor into the equation. I never took them in my life and my son was diagnosed with pdd/nos, adhd. I would eat organic fruit and vegetables and took prenatal vitamins. Didn’t smoke or drink. There has to be common cause. The babies get so many shots when they are very young. Their brains are just developing. We did not get all of those shots when we were that young.They said they did research and there are two schools of thought. Those that say the immunizations are responsible and those that say they are not.One researcher said the preservative Thimerosol(mercury based)in the shots, went directly passed the blood/brain barrier of the brain and in effect singed the neurons.It doesn’t take a rocket scientist to figure out that mercury is not supposed to be in our bodies. And certainly not growing developing babies.MY boy is 11. They had mercury in the shots when he had his. His MRI showed spikes on the brain. Since then,2001 or 2002 they started to take Thimerosol out of the shots. I think it is still in some shots, like the flu shot. I ask my doctor before I or my kids get shots. The shots that they give to babies are too close together, too many at one time and given when they are much to young. My kids got their first shot when they were 2 days old, I believe, in the hospital. I think these matters of immunization need to be handled with the utmost care.

  8. Joan
    June 1, 2011 at 5:11 pm

    Again…..blame the mother.

  9. Sarah
    June 1, 2011 at 5:24 pm

    Who doesn’t take prenatal vitamins 3 months before pregnancy and during the first month of pregnancy? A lot of women–particularly women not planning on becoming pregnant or who don’t think they could become pregnant. I wonder if the group of women who didn’t take the vitamins so early is different in other ways than the early vitamin-taking group. Still, if taking pre-natal vitamins for 3-4 months before you get pregnant can reduce the chances of autism, it’s worth it.

  10. Issy
    June 1, 2011 at 6:16 pm

    REALLY? Precious $$$s were spent on this research? Women gave birth during the Great Depression, during famines, during the war and there were no huge epidemics of autism.

  11. Jo
    June 1, 2011 at 6:19 pm

    Personally, I feel studies like this just make moms feel more guilty about their child’s diagnosis. I physically could not take prenatal vitamins for either of my pregnancies. My daughter was my first pregnancy and was a complete surprise. My pregnancy with her was so hard, I could barely swallow food without my gag reflex making me sick, let alone swallow those huge pills the doctor gave me. I already feel guilty about possibly “giving” her autism (I’m being evaluated for Aspergers and I had postpartum psychosis resulting in two separate hospitalizations). Like I don’t feel guilty enough, now studies like this are showing that if I had only not thrown up every time I tried to take my vitamins, she wouldn’t have autism? Or perhaps it was the study that showed we lived too close to a busy, high traffic California freeway while I was pregnant and she was an infant? Too many people, moms especially, are looking at these studies and blaming themselves for their child being different. Let’s see more research on affordable treatments and education of neurotypical adults.

  12. Jacki Maybin
    June 1, 2011 at 6:24 pm

    I disagree with the above as a major finding. I very specifically and intentionally started taking Femsyn (Great Earth) time released prenatal vitamins 4 mos before conceiving each of my sons. I additionally had my husband taking a multi vitamin 4 mos before trying to conceive. My sons were both planned. Both are on the Autism spectrum. My older son is more severe. One thing I cant find any study on and that probably can’t be verified, is I see a lot of twins (only 1 being affected) a lot through out the school system. Because of my age (just under 40yrs at time of his birth) I had an ultra sound at 8wks. At that time, My son was twins. By the time I had my 12wk ultra sound, the twin had reabsorbed back into my body. My obgyn called it vanishing twin syndrome. I often wonder if there having been 2 initially, somehow triggered the issues. Other questions of potential causes for me would be cord wrapped around his neck twice with distress, maconium at birth, had epidural when fully dilated to delay delivering while another patient got a c-section, was given nubain to relief pain as i couldnt get epidural, given hepituts B shot on day 2 of life, my husband & I both being 39yrs old at time of conception. All these things makes me wonder. Anyone have any additional insight?

  13. Tricia Goodrich
    June 1, 2011 at 7:34 pm

    I took my prenatal vitamins every day. Even made sure I was taking the healthiest ones with increased DHA. I did not smoke or drink no caffeine,ate all the right foods and exersized. The only thing that I can possibly pinpoint is those immunization shots at 12 months that everyone says your child has to have or else you are an unfit parent,promoting prenatal vitamins before during and after is important but what about those who did all of the above?

  14. Susan R
    June 1, 2011 at 11:37 pm

    Sounds to me like one more way to try to blame the mother. With so many variables and interactions, why lay this on parents now? Sounds like plenty of women who took prenatal vitamins before they were pregnant (hmmm, should those be renamed pre-pregnancy vitamins?) still have children on the spectrum. Could the study authors please address this issue? Thanks.

  15. Katherine
    June 2, 2011 at 2:32 am

    I disagree, I have had 4 full-term pregnancies and was unable to take prenatal vitamins during all pregnancies and only one out of 4 has Autism. My child with Autism is my fourth child. I appreciate the study, but I believe that these studies should take into account a lot more feed back from the parents of these children. It is always easier to blame a disorder or disease on something organic, that you may have or may not have taken as the cause.

  16. June 10, 2011 at 9:58 pm

    I agree with many other commentators in that taking your prenatal vitamins is just one piece of the puzzle in the autism rates increase. However, it’s a piece I am still happy to have! I read in another article that if a woman does not take her prenatals she increases her chance of having a child with autism by 60% – which I have a hard time imaging frankly.

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