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The Impact of Folic Acid and MTHFR on Pregnancy

The Impact of Folic Acid and MTHFR on Pregnancy

So many people have questions about the MTHFR gene variation.

Here are some key insights, especially around how this may affect healthy pregnancies.

What is MTHFR?

Methylenetetrahydrofolate Reductase (MTHFR) is the rate-limiting enzyme in the methylation cycle, and it is encoded by the MTHFR gene.

When it comes to MTHFR, understand that there are two possible variations one can have.

You can have the C677T gene variation or the A1298C gene variation. They’re a little bit different, and it is worth noting that the C677T seems to be the more commonly implicated one with autoimmunity.

The implication of the MTHFR gene variation is poor methylation.

And, if you don’t already know, methylation is the process of transferring a methyl group, such as to our DNA, to turn our genes on or off.

"One of the things that we’re going to see is that people with MTHFR are not going to properly absorb folic acid, which is a synthetic version of folate that’s present in many cheap over-the-counter multivitamins, and it’s also added to some of our food to prevent birth defects."  ~Dr. Ben Lynch

Those with MTHFR may actually show normal levels of folate on their lab tests, but it actually looks at their folic acid levels. Folic acid is not the usable form of folate for our bodies, so make sure you are getting the right form of folate, methylfolate, in your diet and supplements.

Avoid folic acid, because it can “sit” in the body's folate receptors and not activate them properly.

MTHFR may also show up as high homocysteine levels and/or blood clotting, and can put you at greater risk of heavy metal toxicity.

It is important to remember that if you’re pregnant, having the MTHFR gene variation does not spell disaster, but it is something to be aware of and educated about.

One of Dr. Lynch's greatest passions is to help educate you on this matter. It can be hard to research this yourself because there is so much conflicting evidence – Some papers say MTHFR is associated with recurrent miscarriage and others say it is not.

(Dr. Lynch wants to share this critical new study abstract on the implications of MTHFR & folic acid, see below for the full abstract.)

Why are there contradictory results?

Some women with MTHFR variations already may be consuming leafy green vegetables, limiting folic acid intake and have their methylation cycle working well. Other women with MTHFR variations make different environmental choices and their methylation cycle is not working well.

So, it depends on your life choices such as diet, stress, etc. Just because you have a MTHFR variation does not automatically mean you are going to have recurrent miscarriages.

What having a MTHFR variation does mean is that you have an increased risk for recurrent miscarriages (and other possible conditions).

If you are having recurrent miscarriages, you seriously need to consider doing genetic testing with your doctor.

Consider removing folic acid and start using more active forms of folate which your body – and your baby – can efficiently use.

MTHFR and Genetic Testing: Dr Lynch recommends AncestryDNA 2.0 or 23andMe Testing as it provides a comprehensive view of one’s genetics – much more than MTHFR. (Yes, 23andMe does test for MTHFR.)

And be sure to use StrateGene to point out key gene variations such as MTHFR.

If you have any experiences related, we'd love to hear them. Please comment below.

Want sound research on the relation between MTHFR and pregnancy? Read the study abstract presented below from the National Institutes of Health:

MTHFR isoform carriers. 5-MTHF vs folic acid: a key to pregnancy outcome: a case series.


To evaluate the possibility of correcting metabolic defects in gametes and embryos due to methylene tetra hydrofolate reductase (MTHFR) isoforms C677T and A1298C, by supplementation with 5-methyl THF instead of synthetic folic acid. In these couples, high doses of folic acid lead to UMFA (un-metabolized folic acid) syndrome.


Thirty couples with fertility problems lasting for at least 4 years, such as recurrent fetal loss, premature ovarian insufficiency, or abnormal sperm parameters, with two thirds of them having failed assisted reproductive technology (ART) attempts were included in this program. For all couples, at least one of the partners was a carrier of one of the two main MTHFR isoforms. Most of the women had been previously treated unsuccessfully with high doses of folic acid (5 mg/day), according to what is currently proposed in the literature. The couples carrying one of the isoforms were treated for 4 months with 5-MTHF, at a dose of 600 micrograms per day, before attempting conception or starting another attempt at ART. The duration of treatment corresponding to an entire cycle of spermatogenesis is approximately 74 days.


In this first series of 33 couples, one couple was not followed-up, and two are still currently under treatment. No adverse effects were observed. Thirteen of the couples conceived spontaneously, the rest needing ART treatment in order to achieve pregnancy. Only three couples have, so far, not succeeded.


The conventional use of large doses of folic acid (5 mg/day) has become obsolete. Regular doses of folic acid (100–200 μg) can be tolerated in the general population but should be abandoned in the presence of MTHFR mutations, as the biochemical/genetic background of the patient precludes a correct supply of 5-MTHF, the active compound. A physiological dose of 5-MTHF (800 μg) bypasses the MTHFR block and is suggested to be an effective treatment for these couples. Moreover, it avoids potential adverse effects of the UMFA syndrome, which is suspected of causing immune dysfunction and other adverse pathological effects such as cancer (especially colorectal and prostate).

Source: National Institutes of Health – 5-MTHF vs folic acid: a key to pregnancy outcome: a case series.  

Other Resources To Check Out:

Folic Acid YouTube Playlist - Catch up on all the informative videos Dr. Lynch has on the topic of folic acid.

Dr. Lynch breaks down the formulation of the Optimal Prenatal line in this blog! He also details other essential nutrients needed during pregnancy. It's a must read!


Did you know that the Optimal Prenatal line took three years to formulate. For more details on the ingredients in the Optimal Prenatal line, click here for a FREE guide.

If you have any experiences related or questions, please comment below.

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