Can Folic Acid Become Poisonous To Pregnant Women?

We all know that pregnant women need folic acid, right? The reality is that for 10-15 percent with a genetic condition, folic acid could be dangerous.

If you’re a woman of childbearing age, you’ve undoubtedly been told by your obstetrician, family practice physician, and even your mom and girlfriends that you need to be taking folic acid to prevent birth defects. Well, they’re mostly right.

Folic acid is a b-vitamin that is essential in promoting cell growth and is critical in the prevention of birth defects like spina bifida and anencephaly, both of which can be fatal. Most doctors agree that women of childbearing age do not get enough folic acid. In fact, in March of this year, the Journal of the American Medical Association released a new study entitled, “Higher Folic Acid Intake Needed.” The study, which measured the occurrence of neural tube defects (NTDs) such as spina bifida and anencephaly, concluded that because the number of NTDs has not decreased in the last 15 years, U.S. women are still dealing with insufficient folic acid reserves.

In 1998, the U.S. Department of Agriculture began fortifying grains with synthetic folate in an effort to prevent NTDs. In 1999-2000, a brief decline in NTDs was observed, but as the JAMA study noted, rates really have remained the same ever since, leading the conclusion that folic acid levels remain insufficient.

What the JAMA study failed to mention is that a significant population exists in the U.S. that are unable to process folic acid.

While there is no solid consensus, it is believed that anywhere from 10 to 15 percent of Caucasians and more than 25 percent of Hispanics are unable to metabolize folic acid. This defect, called methylenetetrahydrofolate reductase, or MTHFR for short, refers to the MTHFR gene which produces the enzyme responsible for converting synthetic folic acid to methylated folate, which is the essential metabolized nutrient that protects against NTDs.

“I think we’re at the very beginning of being able to understand [MTHFR],” says Diane Keddy, a dietician and nutritionist based in Newport Beach, California. “A lot of physicians don’t know anything about it. It’s like where Celiac’s Disease was 10 years ago. MTHFR is a little-known but incredibly common defect that currently affects several million people in the U.S.”

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According to Keddy, the basics of MTHFR boil down to the following: a huge subset of the U.S. population has some sort of MTHFR defect, and the defect can present itself in several different ways. Although many people have MTHFR defects, not all defects manifest themselves in symptoms. Symptoms can range from mild (migraines, anxiety, depression, increased risk of birth defects) to severe (recurrent and unexplained pregnancy loss, blood clots, or unexplained, early-onset heart disease, strokes and even certain types of cancers). There is good news for testing, as a blood panel or a simple saliva test can determine whether someone has the MTHFR gene.

At Woodlands OBGYN Associates, we are highly aware that MTHFR defects are more prevalent among women, and we understand that women of childbearing age are more likely to be challenged into taking folic acid; however, when women with the MTHFR defect take synthetic folic acid that they are unable to metabolize, there is a folic acid build up in the body that becomes toxic and can trigger the growth of pre-cancerous cells. This toxic build up can exacerbate MTHFR-related symptoms like migraines and blood clots, and can cause recurrent miscarriages. Additionally, the inability to synthesize folic acid has been associated with multiple pulmonary embolisms, symptoms of which include shortness of breath and chest pains. Pulmonary embolisms (PE) can be fatal in 15 percent of cases, and are an associated lethal side effect of the MTHFR mutation.

For women who test positive for the MTHFR mutation, Keddy recommends several things to her patients.  “The first things I tell them is to avoid folic acid. This means going completely gluten-free, because there’s synthetic folic acid in almost all breads and cereals,” says Keddy. Another recommendation is clean eating and avoiding exposure to chemicals such as alcohol, NSAIDs, or other chemicals, because amino acids that are involved in liver detoxification are usually impaired as well.

As for supplementing foods with folic acid, Keddy isn’t so sure. 

“I think it needs to be discontinued until proven safe for women with MTHFR. Anyone who has a family history of infertility, heart disease, strokes, miscarriages, birth defects—they should get tested,” she says. “I think everyone would benefit from knowing their MTHFR status.”

Here at The Woodlands OBGYN Associates, we perform a blood test to test for the MTHFR mutation on patients we suspect may have a problem. Knowing your MTHFR status is crucial to our understanding of your response to folic acid and the success of a healthy pregnancy. 

If you know you are pregnant – or you think you might be – call us today to schedule this important screening to help ensure your pregnancy success.

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Monday – Thursday: 8 AM – 5 PM
Friday: 8 AM – 12 Noon
Location Map: 17183 I-45 The Woodlands, TX 77385

The Woodlands Office



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