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Defective MTHFR Gene Linked to Fertility and Pregnancy Struggles

Defective MTHFR Gene Linked to Fertility and Pregnancy Struggles

The B vitamin Folic Acid has been touted as the most important vitamin for the proper development of a baby in pregnancy. This is especially true for the first few weeks of pregnancy, when the spinal column is developing. Research shows that folic acid plays a critical role in preventing the neural tube defect called spina bifida. It is considered so important, that the March of Dimes has an entire campaign focused on educating the public about the importance of women in their childbearing years, getting the right amount of this vitamin daily.

What if your body has a genetic defect that makes it extremely difficult for your body to utilize folic acid properly, though? And how would you even know? For 1 in 4 people this is a serious reality and if left undiagnosed, may lead to a variety of pregnancy-related issues including difficulties conceiving, unexplained infertility, elevated homocysteine levels, recurrent miscarriages, child with Down Syndrome, development of Autism*, preeclampsia, postpartum depression, or even the development of chronic depression.

What is this genetic defect?
It is a defect of the MTHFR (Methylenetetrahydrofolate reductase) gene, known as MTHFR C677T. MTHFR is a gene in the body that plays a key role in the proper function of many body systems. Let’s learn more about how this relates to folic acid utilization…

The Role of MTHFR in Utilizing Folic Acid and Folate

To begin, it is important to know that the MTHFR gene resides in each and every cell in the body. It is responsible for utilizing folic acid and producing the most active form of folate called methylfolate. People with the variant MTHFR C667T have a 40 – 60% decreased ability to produce methylfolate.

Why is Methylfolate so Important?
In the body, methylfolate starts an innumerable amount of critical enzymatic reactions. This impacts the body’s ability to produce a compound known as s-adenosylmethionine, SAMe for short. The body needs SAMe to produce CoQ10, carnitine and creatine, all of which play a critical role in the body’s ability to reproduce, not to mention maintain a variety of other body systems.

MTHFR C677T gene defect contributes to elevated homocysteine levels, which are commonly linked to recurrent miscarriages, as well as the other pregnancy related risks I spoke of previously.

How does MTHFR gene defect cause elevated homocysteine levels?
One by-product of SAMe is homocysteine. Methylfolate and methylcobalamin help to convert harmful homocysteine into the beneficial methionine, which in turn helps to produce SAMe, in a cycle that is never ending, as long at the body is producing methylfolate. In the case of MTHFR gene defect, homocysteine levels may rise to harmful levels due to the impaired ability to produce adequate amounts of methylfolate; impacting your ability to conceive or harming an otherwise healthy pregnancy.

Other concerns with this wheel are that the body will poorly convert homocysteine to the powerful antioxidant glutathione, which helps protect the body from free radical damage. People with compromised antioxidant levels are more susceptible to oxidative damage due to stress and environmental toxins, thus increasing the risk for toxin build-up. In addition, people with MTHFR gene defect may have lower levels of SAMe, which has been shown to increase the development of depression and postpartum depression. SAMe also plays an important role in immune system function, growth, and repair and maintenance of cells; it is also anti-inflammatory. All of these play a role in reproductive function and proper development of a baby in pregnancy.

Testing is Easy!

If you have been struggling to get pregnant, have experienced recurrent miscarriages or any of the other pregnancy-related issues I mentioned previously, schedule an appointment with your doctor for a MTHFR genetic test and blood homocysteine level. This should be done before you try to get pregnant again.

Results Matter – Heterozygous or Homozygous?
There are different variations of the MTHFR gene defect. There are people with heterozygous (1 copy of C677T, passed on from one parent) and homozygous (2 copies of C677T, passed on from both parents) MTHFR mutations. Those with homozygous MTHFR C677T are often advised to take their folate requirements more seriously. Homozygous individuals need to avoid synthetic folic acid (see below for more info on this), they require more methylfolate supplementation than heterozygous individuals do and their blood thinning requirements are greater, especially where a woman’s ability to get pregnant and carry to term is concerned. Before a successful pregnancy can be achieved, these considerations must be addressed.

What You Can Do if You Test Positive for MTHFR C677T

Although at first it feels quite scary and hopeless to be diagnosed with a genetic defect, this one is quite common. Fortunately, there are things you can do at home to increase your chances of natural conception, carrying a healthy pregnancy to term, preventing postpartum depression and protecting your health overall, since MTHFR gene defect impacts many areas of health.

Folate rich foods include spinach, lentils, papaya, grapefruit, walnuts, and asparagus.

Folate rich foods include spinach, lentils, papaya, grapefruit, walnuts, and asparagus.

  • Eat organic; this will help reduce overall toxic load.
  • Avoid supplementing with synthetic folic acid; choose a whole food prenatal multivitamin like Baby & Me 2TM Prenatal Multivitamin through pregnancy and breastfeeding. You may also want to ask your doctor about special prenatal vitamins that contain methylated folate or folinic acid.
  • Eat a diet rich in naturally occurring folate, such as uncooked dark leafy green vegetables, lentils, beans, liver, and avocado. For a list of folate-rich foods, click here…
  • Avoid processed foods that are fortified with synthetic folic acid (homozygous) or strictly limit them (heterozygous).
  • Consider supplementing with carnitine, CoQ10 Ubiquinol, cod liver oil, probiotics, and an antioxidant blend. These can all be found in our online store.
  • At each meal, eat a variety of whole foods and be sure to include a protein.
  • Make sure all the B vitamins you supplement are from a whole food source and provide the methylated form (active). For vitamin B6 this would be Pyridoxal 5-Phosphate or P5P; for Vitamin B12 this is methylcobalamin.
  • Avoid regularly consuming both black and green tea, as they may inhibit folic acid absorption.
  • Avoid antacids; these inhibit folic acid absorption as well.
  • According to Dr. Ben Lynch, an expert on MTHFR gene mutation, it is best to avoid birth control use, as this can block folate absorption.
  • For vegans, it is important to speak with your doctor about supplementing with the following, in addition to the above; methylcobalamin (active form of vitamin B12) and choline.
  • Find a good OB/Gyn or midwife to work with that is well educated in MTHFR gene mutation if you plan on getting pregnant. This will help you to maintain the continued support you need through pregnancy and lactation.

If you have tested positive for MTHFR gene mutation, I highly recommend learning more from naturopathic doctor Ben Lynch of He thinks outside the box, provides a wealth of information, and is helpful at directing people to support.

*”The latest research indicates that high folate levels will also lead to autism spectrum disorder so it appears possible that too much folate can also lead to the disorder,” according to Christine Traxler, MD (personal communication). Researchers agree that we need to know if the findings are a result of women eating too many manufactured food products fortified with synthetic folic acid, supplementing with too much synthetic folic acid, lacking in genes and enzymes involved in the metabolism of folic acid and/or folate (from whole foods), or a combination and or all of these things.


Dr. Christine Traxler M.D., OB/GYN
Dr. Christine Traxler M.D., OB/GYN

Dr. Traxler is a University-trained obstetrician/gynecologist, working with patients in Minnesota for over 20 years. She is a professional medical writer; having authored multiple books on pregnancy and childbirth; textbooks and coursework for medical students and other healthcare providers; and has written over 1000 articles on medical, health, and wellness topics.  Dr. Traxler attended the University of Minnesota College of Biological Sciences and University of Minnesota Medical School,  earning a degree in biochemistry with summa cum laude honors in 1981,  and receiving her Medical Doctorate degree (MD) in 1986.

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  1. Avatar

    If you are MTHFR positive you should avoid ALL folic acid. You can only take bio-available forms of Folate (L-5). Folic acid is not Folate. The National Institutes of Health, PubMed Databased has studies on this, that folic acid is toxic to people with the MTHFR mutations. It does not metabolize and studies are showing (in Norway, where enriched folic acid is not added to food) that folic acid may stimulate pre-cancer cells in patients with MTHFR.

  2. Avatar

    Hi I want to ask if men can also take folic acid.

    • Elizabeth Willett, MA, CH

      Hi Debbi!
      In 2008, a study was published in the peer-reviewed medical journal Human Reproduction that showed “a link between high levels of the nutrient [folic acid] in men’s diets and the genetic quality of their sperm.” While concrete conclusions were not made in this study, folic acid is a common nutrient in men’s multivitamins and may support sperm health. If sperm health is a concern also consider reading Sperm: 10 Interesting Facts Everyone Should Know.

  3. Avatar

    what if you have one of each, what is that called?

    • Hi amydk,

      I am not exactly sure what you mean, but when you carry 2 copies of C677T, passed on from both parents, it is called homozygous MTHFR.

    • Avatar

      She is referring to the other MTHFR gene mutation, A1298C. It is possible for a person to have one copy of C677T and one copy of A1298C.

      I highly recommend It is the only place I have found so far with much information about the A1298C mutation, which has not been researched as much.

    • Hi Kathryn,

      Ah, yes, thank you for interpreting that. I too recommend that site in the last paragraph of the article. Dr. Ben Lynch of is the best!

      Thanks for your help.