Methylenetetrahydrofolate reductase (MTHFR) is a rare genetic defect that can lead to complications in pregnancy. Many people do not know that they have this defective gene until after they have had several unsuccessful pregnancies. Others may carry one pregnancy to term and not discover until afterwards that they carry the defect.

What is MTHFR?
Methylenetetrahydrofolate reductase (MTHFR) is the name of a gene that produces an enzyme, also called methylenetetrahydrofolate reductase. If a person carries the genetic mutation that inhibits production of this enzyme, it can result in hyperhomocytenemia, which is an elevated level of an enzyme called homocysteine found in blood plasma.

When the body is deficient in methylenetetrahydrofolate reductase, its ability to absorb folate (also known as vitamin B9), such as folic acid, is inhibited. Folic acid and B9 are both essential to the development and health of the fetus.

Learn more about pregnancy gene mutations.


Because of a mother with MTHFR’s inability to efficiently metabolize folic acid and vitamin B9, the disorder has been linked to a variety of pregnancy complications such as chromosomal abnormalities, such as Down syndrome, and congenital malformations.

Elevated levels of homocysteine have been associated with placental disease, preeclampsia and recurrent pregnancy loss. 21% of women with high levels of homocysteine experience recurrent pregnancy loss.

Because MTHFR is a blood-based disease with many varieties, symptoms vary depending on the exact mutation of the disease. They can include:

  • blood clots
  • depression
  • anxiety


Blood testing is the most accurate way to screen for MTHFR. This is especially true if women have a history of complicated pregnancies, including recurrent pregnancy loss and/or stillbirths, or if they have given birth to a child with neural tube defects, such as spina bifida.

Taking folic acid can help women with certain mutations of the disease. Folic acid can be found in eggs, dark leafy vegetables, such as spinach and broccoli, oranges and orange juice and legumes, such as peas and dried beans. Vitamin supplements also contain folic acid.

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It is very important to supplement with a particular kind of folic acid, L-Methylfolate, if you have an MTHFR mutation. Other forms of folic acid are not assimilated by your body, and you could elevate homocysteine levels and lead to unhealthy conditions by taking regular folic acid. Please include this in your information. You may look up Dr. Ben Lynch, who has done extensive research on MTHFR, for more info.
11 years ago
I had two misscariages between my first and second daughter, and I found out that I have a MTHFR mutation though I do not remember anymore details, but my Dr. prescribed metanx which is 1 mg of methylfolate and B6 and 12 (not sure how much) but I was pregnant again about 6 weeks after starting it and now I have a happy healthy almost 4 month old. The Dr told me that it had to be methylfolate and not just folic acid because my body was not properly converting the folic acid into methylfolate which is what the body normally would do to make the folic acid useful. The metanx got a little expensive so after pregnancy I have gone to supplementing with a separate methylefolate without any iffy ingredients or ridiculous dyes or artificial sweeteners and b6 and b12 in whole food vitamins and I am still having wonderful results with the reduction of depression, anxiety, low energy, and foggy-headedness. Best wishes to all of you ladies out there struggling with these problems and I hope this will help. I also have a sister with a MTHFR gene mutation and am thinking about looking in to how to test my oldest daughter as she may not be getting proper folic acid conversion from her body either...
13 years ago
my doctor actually suggested taking a folic acid supplement at least three months prior to trying to get pregnant even though we don\'t know if i have this condition. i think she told me to take at least 400mg of folic acid daily to help prevent birth defects like spina bifida and heart murmurs. she said you should start taking folic acid months before trying to get pregnant because then you can ensure having enough folic acid in your system when you do actually get pregnant since most women don\'t know they are pregnant for the first few weeks since there are very few early pregnancy symptoms during this time and if you wait to take folic acid after you know you are pregnant then it is already too late.
13 years ago