• Weil Nutrition Corner
  • Meet Dr. Weil
  • Origins
  • Healthy Aging
  • Marketplace
  • Podcasts
  • Accessibility
  • Subscribe
Dr. Weil Logo Dr. Weil Logo Weil™ Andrew Weil, M.D.
  • Health & Wellness
    Health & Wellness
    Body, Mind & Spirit
    • Addiction
    • Allergy & Asthma
    • Autoimmune Disorders
    • Back Pain
    • Bone & Joint
    • Cancer
    • Colds & Flu
    • Dental & Oral
    • Diabetes
    • Disease & Disorders
    • Ears, Nose, & Throat
    • Feet
    • Gastrointestinal
    • Hair, Skin, & Nails
    • Headache
    • Heart
    • Insects & Parasites
    • Liver & Kidney
    • Mental Health
    • Pregnancy & Fertility
    • Respiratory
    • Sexual Health
    • Sleep Issues
    • Stress & Anxiety
    • Vision
    Balanced Living
    • Exercise & Fitness
    • Gardening
    • Healthy Home
    • Healthy Living
    • Meditation & Inspiration
    • Meet Dr. Weil
    • Pets & Pet Care
    • Technology
    • Wellness Therapies
    Health Centers
    • Aging Gracefully
    • Children
    • Condition Care Guide
    • Men
    • Women
  • Diet & Nutrition
    Diet & Nutrition
    Anti-Inflammatory Diet & Pyramid
    Cooking & Cookware
    Diets & Weight Loss
    Food Safety
    Nutrition
    Recipes
  • Vitamins, Supplements & Herbs
    Vitamins, Supplements & Herbs
    Herbs
    Supplements & Remedies
    Vitamins
  • Ask Dr. Weil
  • Blogs
    Blogs
    Bulletins
    Health Tips
    Spontaneous Happiness
  • Mushrooms
  • Sleep
Press "Enter" to search
Dr. Weil Logo Weil™ Andrew Weil, M.D.
  • Health & Wellness
    Health & Wellness
    Body, Mind & Spirit
    • Addiction
    • Allergy & Asthma
    • Autoimmune Disorders
    • Back Pain
    • Bone & Joint
    • Cancer
    • Colds & Flu
    • Dental & Oral
    • Diabetes
    • Disease & Disorders
    • Ears, Nose, & Throat
    • Feet
    • Gastrointestinal
    • Hair, Skin, & Nails
    • Headache
    • Heart
    • Insects & Parasites
    • Liver & Kidney
    • Mental Health
    • Pregnancy & Fertility
    • Respiratory
    • Sexual Health
    • Sleep Issues
    • Stress & Anxiety
    • Vision
    Balanced Living
    • Exercise & Fitness
    • Gardening
    • Healthy Home
    • Healthy Living
    • Meditation & Inspiration
    • Meet Dr. Weil
    • Pets & Pet Care
    • Technology
    • Wellness Therapies
    Health Centers
    • Aging Gracefully
    • Children
    • Condition Care Guide
    • Men
    • Women
  • Diet & Nutrition
    Diet & Nutrition
    Anti-Inflammatory Diet & Pyramid
    Cooking & Cookware
    Diets & Weight Loss
    Food Safety
    Nutrition
    Recipes
  • Vitamins, Supplements & Herbs
    Vitamins, Supplements & Herbs
    Herbs
    Supplements & Remedies
    Vitamins
  • Ask Dr. Weil
  • Blogs
    Blogs
    Bulletins
    Health Tips
    Spontaneous Happiness
  • Mushrooms
  • Sleep
  • Weil Nutrition Corner
  • Meet Dr. Weil
  • Origins
  • Healthy Aging
  • Marketplace
  • Podcasts
  • Accessibility
  1. Home
  2. Health & Wellness
  3. Health Centers
  4. Children

Does Folate Cause Autism?

I’m confused about folate. I’ve heard that taking it during pregnancy can lower – or raise – the risk of autism. Which is right?

Andrew Weil, M.D. | August 30, 2018

does folate cause autism
2 min

Pregnant women have an increased need for folate. Folate occurs naturally in dark leafy greens, fruits, nuts, beans and other foods; folic acid is the synthetic form in supplements. Vitamin B9 supports the growth of the placenta and fetus and helps prevent several types of birth defects, especially those of the brain and spine. Women of child-bearing age, pregnant or not, should make an effort to get enough folic acid. Women who are pregnant and nursing should discuss the amount they need with their obstetrician.

The autism question has generated considerable confusion, but there is very little evidence that taking folic acid during pregnancy increases the risk. A study published in February 2018 reviewed its effects on the known risk of autism in children who were exposed to drugs for epilepsy before birth. (We don’t know how these medications increase risk, but they do.) Researchers in Norway looked at data from 104,946 births between 1999 and 2008, focusing on those in which 288 women took epilepsy drugs while pregnant. Results showed a higher risk of autism among children whose mothers did not take folic acid while pregnant than among the children of women who did take it. The study found that 32 percent of children whose mothers took epilepsy drugs but did not take folic acid showed autism traits at 18-months of age, and 26 percent showed these traits at 36 months. Among children whose mothers took drugs for epilepsy and also took folic acid, only nine percent showed autism traits at 18 months and 6 percent at 36 months.

A study in California looked at autism rates among children whose mothers were exposed to insecticides prior to giving birth. In this group, they found that women whose folic acid intake was above average were 1.3 to 1.9 times more likely to have a child with autism compared to women who had no pesticide exposure. Women exposed to pesticides whose folic acid intake was less than average had about twice the risk of having an autistic child.

The possibility that folate increases the risk of autism was first proposed by investigators from Johns Hopkins Bloomberg School of Public Health in 2016. They found that women who took a multivitamin three to five times a week had a lower chance of having an autistic child. But following that, the researchers reported that women with excessively high levels of folate or vitamin B12 in their blood around the time of giving birth had an increased risk of having a child who develops autism. This made headline news. The investigators had no information about the women’s use of supplements and no idea why their blood levels of folate were so high. There may be a subset of women with excessively high blood levels of folate that might put their children at risk for autism.

The latest word on this issue comes from a study published in January 2018, in which the researchers said their finding “raises new questions about the impact of extremely elevated levels of plasma folate and vitamin B12 exposure in-utero on early brain development.” But they emphasized that this doesn’t negate the importance of taking adequate folic acid and vitamin B12 during pregnancy.

Andrew Weil, M.D.

 

Sources:
Marte Bjork et al, “Association of Folic Acid Supplementation During Pregnancy with the Risk of Autistic Traits in Children Exposed to Antiepileptic Drugs In Utero.” JAMA Neurology, February 1, 2018, doi:10.1001.jamaneurol.2017.3897

Ramkripa Raghavan et al, ”Maternal Multivitamin Intake, Plasma Folate and Vitamin B12 Levels and Autism Spectrum Disorder Risk in Offspring.” Paediatric and Perinatal Epidemiology, January 2018, doi: 10.1111/ppe.12414

Read more tips, recipes, and insights on a wide variety of topics from Dr. Weil here.

air pollution affect childrens behavior
Children

Does Air Pollution Affect Children's Behavior?

cure for autism
Children

An Autism Cure?

Dr. Weil on Healthy Aging

Start Your 14-Day Free Trial

Free Newsletters

Stay Connected With Dr. Weil

Anti-Inflammatory Diet

Follow Dr. Weil’s Food Pyramid

Get Dr Weils Newsletter Updates

Exclusive Lifestyle, Nutrition & Health Advice

Dr. Weil's FREE health living advice delivered to you!

By clicking "Subscribe," you agree to the DrWeil.com Terms and Conditions and Privacy Policy. You also agree to receive emails from DrWeil.com, and you may opt out of DrWeil.com subscriptions at any time.

Trending Now

Closeup photo of caring mother holding head on sick daughter forehead
Children

A Mystery Disease in Children?

Mom giving medicine to little girl – I
Children

A Placebo Pill to Comfort Kids?

Acupuncturist prepares to tap needle into patients hand
Children

Acupuncture for Children

Child having points stimulated during an Acupuncture Session.  The style being used was Japanese Acupuncture called Toyohari.  The tool in the picture is called Teishin.
Children

Acupuncture for Kids?

Dr. Weil Logo Weil™ Andrew Weil, M.D.
Dr. Weil's Signature

Exclusive Lifestyle, Nutrition & Health Advice

  • About Us
  • Press Information
  • Advertising
  • Contact Us
  • Terms of Use
  • Privacy Policy
  • Accessibility

Terms of Use | Privacy Policy

Information on this website is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not use the information on this website for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment. Any third party offering or advertising on this website does not constitute an endorsement by Andrew Weil, M.D. or Healthy Lifestyle Brands.

© Copyright 2025 Healthy Lifestyle Brands, LLC. All rights reserved. Reproduction in whole or in part without permission is prohibited. www.drweil.com