Study: Excess Folic Acid During Pregnancy Has Autism Link

We’ve long known that a deficiency in folic acid during pregnancy can be harmful to fetal development, but a new study suggests that an excess of folic acid may have similar consequences.

16 week fetus

The new study suggests that excessively high levels of folic acid in pregnant women appears to increase the risk of autism.

Folate is a naturally-occurring B vitamin that doctors consider essential for proper neurological development in the fetus. Folic acid is the supplemental form of the vitamin and is frequently recommended to help prevent birth defects – and coincidentally, to reduce the risk of autism spectrum disorder.

There is a very complex relationship between the vitamin and the ASD disorder, so it is critical for medical professionals to realize that excessive levels of folic acid can be equally as dangerous as a deficiency. The challenge is finding the right balance.

The Centers for Disease Control and Prevention (CDC) report that 25% of women of reproductive age in the US do not get enough folic acid through their diet. That’s why the supplement is so commonly prescribed during a pregnancy, but the newly-released study raises some red flags on the consequences of overloading on something generally considered good for mothers and their unborn child.

Excess vitamin B12 in new moms was linked to a tripled risk of the child developing autism disorders. When both folic acid and vitamin B12 levels were too high, that risk increased by a factor of 17.6 times. Too much of a good thing is…bad.

The researchers measured blood folate levels in new moms within the first three weeks following delivery. Autism Canada executive director Laurie Mawlam says that the study “raises concerns” and she believes more research is needed to understand the complicated relationship between vitamins and ASD.

Canadian researcher Young-in Kim, a professor of medicine at the University of Toronto points out that in other studies on both humans and animals research shows “that too much folic acid during a pregnancy may cause allergies, asthma, and an increased risk of cancer and cognitive dysfunction.”

There are no well-established guidelines for adequate vitamin B12 levels during pregnancy, and factors such as diet and a woman’s own genetic makeup will have an effect on how supplements are processed by the body.

The bottom line is that mothers who have moderate blood levels of folate and the related vitamin B12 in their blood at the time of birth have a lower risk of delivering a child with an autism disorder.

The findings from the study will be presented at the 2016 International Meeting for Autism Research this week in Baltimore, Maryland.


About the author


Vicki Clinebell is a former television advertising executive who spent 25+ years with an ABC television affiliate in sales and marketing. A journalism major in college at the University of Colorado/Boulder, she now writes for a variety of online and print publications and provides blog content for clients including retail businesses and artists. The diversity of subject matter appeals to her, whether she’s reporting on the latest trends in baby gear, highlighting stories about outdoor adventures, or explaining basic pet-care tips. Even better, she says, is the shorter work commute… just down the hall, and a dress code that’s changed from suits and heels to jeans and a sweatshirt.

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