What is the MTHFR Mutation?
The MTHFR Mutation is a change in the DNA that codes for a different gene. This gene affects your body’s ability to metabolize folic acid and maintain a healthy concentration of folate in your blood. There are actually 2 genes that work together to metabolize folic acid. Some people have a mutation of one gene, and other people have a mutation of both genes. The main 2 mutations are C677T and A1298C. In research, it appears that a C677T mutation is associated with recurrent pregnancy loss. However, A1298C is not associated with pregnancy loss.
The increased risk of pregnancy loss, or miscarriage, is thought to be associated with a decrease in folate. Folate is essential for a pregnancy to continue. In one study from 2017 of women with the MTHFR gene mutation, supplementation with folate (methyl-folate), vitamin B6 and vitamin B12 improved pregnancy outcomes.
Active folate is also essential in the prevention of neural tube defects. In one meta-analysis, women with the C677T mutation were found to have an increased risk of having a child with an open neural tube defect, such as spina bifida. However, when women with the MTHFR mutation receive additional folate supplementation, the risk of neural tube defects decreases.
How Common is the MTHFR Gene Mutation?
The MTHFR mutation is actually very common. For example, approximately 30-50% of the US population has a MTHFR gene mutation. In fact, in some select populations, the prevalence could be over 50%. In the US, it is estimated that 12% of the white population has 2 copies of the C677T mutation. Only 1% of the black population has 2 copies of the C677T mutation. However, in California, 21% of the Hispanic population has 2 copies of the C677T mutation. And to review, 2 copies of the C677T mutation is the genotype that has the largest effect on fetal outcomes.
The MTHFR mutation is much more common that many people realize. This mutation could therefore have an effect on many women’s risk of miscarriage and neural tube defects.
How Do I Know if I have the MTHFR Mutation?
Most people don’t know. This is because the mutation doesn’t generally cause any symptoms. The American College of Medical Genetics and Genomics and The American Congress of Obstetricians and Gynecologists recommend against universal screening for the MTHFR mutation. Their reasoning is that with standard folate supplementation and a healthy diet, the evidence is not strong enough to suggest additional risk. So if you want to be tested for the MTHFR mutation, your doctor may or may not offer this test. You could choose to seek out a genetic counselor.
Another option would be to do 23andMe and then search your raw data for the MTHFR gene mutation. You can use Genetic Genie to search your raw data for the MTHFR mutation. For directions on how to do this, go to Genetic Genie. To order 23andMe, go to Order 23andMe.
However, if you don’t know if you have the mutation and you don’t want to spend the time and money on testing you can still protect yourself and your pregnancy. Just assume you carry the mutation, and follow my recommendations below.
What Should I Do if I Have the MTHFR Mutation?
Women with the MTHFR gene mutation do not efficiently metabolize folic acid, or folate. However, methyl-folate, found in some prenatal vitamins, is already active. This enables the folate to successfully enter the bloodstream.
Therefore I recommend that women with the MTHFR mutation, or women who don’t know if they have the MTHFR mutation, select a prenatal vitamin with methyl-folate.
There is no harm to taking a prenatal vitamin with methyl-folate. So you may as well play it safe. Many of the vitamins that contain methyl-folate are overall good prenatal vitamins. To find out more about selecting a prenatal vitamin, check out this article. For your convenience I have listed some examples of vitamins that contain methyl-folate below.
What Does This Mean for Me?
Don’t worry about understanding how your body metabolizes folic acid. Instead understand that in vitamins not all folate supplements are equal. Folate is essential for fetal development. So it is important to make sure you are absorbing enough folate. When selecting your prenatal vitamin, look at the nutrient info on the back of the bottle.
- “Folic acid” is the most difficult to absorb.
- “Folate” is absorbed moderately well.
- “Methyl-folate” is the easiest form for your body to absorb.
To be safe, look for a vitamin with methyl-folate.