MTHFR Mutations and Fertility

If I got a dime after time I heard/saw women who were given by their doctor extra folic acid because they have an MTHFR mutation, I would be a millionaire.


But this is beyond sad; it is entirely wrong, from a scientific and medical point of view. I am going to explain what are the MTHFR mutations, why it is sooo bad to prescribe extra folic acid to a patient who has them and what are the solution and precautions. By the end of this article you will feel as upset as I am when you hear that someone with MTHFR mutation has been prescribed extra folic acid.

Make no mistake, this is a topic of monumental importance for fertility, pregnancy and baby health. In my previous article folate vs folic acid, I explained that these two different forms of vitamin B9 are metabolized in a different way and in fact in different organs of the body.

The conversation about MTHFR mutations, has nothing to do with folate or folic acid, because both of these forms of vitamin B9 are inappropriate and potentially dangerous for your fertility and general health.

What are the MTHFR mutations?


of people are estimated to carry MTHFR mutations!

MTHFR is a gene in our DNA, which encodes the MTHFR enzyme. This is THE most critical enzyme for converting folate AND folic acid to methyl-folate, which is then used by the body easily. When the MTHFR genes are fully functional, the correct form of the MTHFR enzyme is produced in the body and metabolism of folate and folic acid takes place normally, as described in the relevant article. When there is a mutation in the MTHFR gene, the MTHFR enzyme is defective and BOTH folate and folic acid can´t be fully converted to methyl folate.

About 30% of the people are estimated to carry MTHFR mutations (that´s A LOT of people!), which result in a genetically reduced ability of the body to use either folate or folic acid. The reduction in the body´s ability to use folic acid and folate depends on the type of the MTHFR mutation (there are several) and how many copies of the mutated gene a patient has (1 or 2).

People carrying MTHFR mutations can only partially convert folate or folic acid to methyl-folate, whether the nutrients come from supplements or natural whole foods.

This is why it is entirely pointless to recommend extra folic acid, or folate to patients that have MTHFR mutations. You are only giving them more of what they cannot use and as I explained in the article folate vs folic acid, having unprocessed folic acid or folate circulating in the body is very unhealthy and can be the source of very different health problems, including repeated miscarriages (recurrent pregnancy loss) [6].

Types of MTHFR mutations

There are different MTHFR mutations, which affect more or less this vital conversion of folic acid and folate to methyl-folate.

Two of the most well-studied MTHFR mutations are called C677T and A1298C. Remember that we have two copies of each gene in our DNA; one from the mother and one from the father, so each one of us has two MTHFR genes. If only one of them have the C677T mutation, the precious MTHFR enzyme functions at 70%, but when both copies of the gene have the C677T mutation, then we are left with only 30% of the original capacity to produce methyl-folate.

The A1298C mutation has a lesser impact in methyl-folate production. When both MTHFR genes have this mutation, we preserve a decent 70% of our ability to process folate and folic acid.