Can You Have a Successful Pregnancy with MTHFR?

Medically reviewed by Rachel Liberto, RN on April 4, 2017Written by Rachel Liberto, RN


Every human body has the gene 5-methyltetrahydrofolate, also known as MTHFR.

MTHFR is a gene that’s responsible for the breakdown of folic acid, which creates folate. Medical disorders can result without enough folate, or with a malfunctioning MTHFR gene.

During pregnancy, women who test positive for a mutated MTHFR gene may have a higher risk for miscarriages, preeclampsia, or a baby born with birth defects such as spina bifida.

Here’s what you need to know about getting tested for this gene and how it might impact your pregnancy.

What does the MTHFR gene do?

MTHFR handles the breakdown of the vitamin folic acid, leading to elevated levels of homocysteine. Homocysteine is a chemical produced from an amino acid in our bodies when folic acid breaks down. If folic acid isn’t broken down, it will block the body’s ability to have enough folate. Hyperhomocysteinemia is a condition where the homocystine levels are elevated. Hyperhomocysteinemia is often seen in positive MTHFR patients because of the mutated gene. High homocystine levels, especially with low folic acid levels, can lead to pregnancy complications that include:

  • miscarriage
  • preeclampsia
  • birth defects

The two most common genes tested in the MTHFR test are C677T and A1298C. If the person tested has two of the C677T gene, or a C6771 and one A1298C, the test often shows elevated homocysteine levels. But two A1298C genes usually are not associated with elevated homocysteine levels. It’s possible to have a negative MTHFR gene test and have high homocysteine levels.

Folate is responsible for:

  • making DNA
  • repairing DNA
  • producing red blood cells (RBCs)

When the MTHFR gene fails, folic acid isn’t broken down. This is known as a mutated MTHFR gene. It’s not uncommon to have a mutated gene — up to 20 percent of the population does.

Risk factors for positive MTHFR gene

The positive MTHFR gene is passed from the parents to the child. Nothing causes you to have a mutated MTHFR gene; it’s simply passed onto you from your mother and father.

You may be at risk if you’ve had:

  • recurrent pregnancy losses
  • an infant with a neural tube defect like spina bifida or anacephaly
  • a history of preeclampsia

What are the complications of MTHFR mutations?

There are different types of mutations that can happen with this gene. Some of them can affect pregnancy more than others. Mutations can also affect other bodily systems like the heart. There’s no scientific evidence that MTHFR gene mutations cause recurrent pregnancy loss, but women who’ve had multiple losses often test positive for the MTHFR gene mutation.

Pregnant women who have a positive MTHFR mutated gene may go on to have complications during pregnancy. These can include:

  • Spina bifida: A birth defect where the spinal cord sticks out of the baby’s back, creating nerve damage. Depending on the severity of the spina bifida, some children go on to have normal lives, while others need full-time care.
  • Anencephaly: A serious birth defect where a baby is born without parts of their brain or skull. Most babies don’t live past one week of life.
  • Preeclampsia: A condition involving high blood pressure during pregnancy.

Testing for MTHFR

It’s not standard protocol to test every pregnant woman for the existence of a mutated MTHFR gene. It can be very costly to do so, and insurance doesn’t always cover it. But if you’ve had multiple miscarriages, have a family history of MTHFR gene or genetic issues with another pregnancy, your doctor may order this test. Results are usually available in one to two weeks.

Positive mutated MTHFR gene treatment options

Treatment for the positive MTHFR gene malfunction is still being studied, but many doctors will prescribe therapy to help prevent blood clotting or increase folic acid levels.

Your doctor might recommend the following options.

Lovenox or heparin injections: These injections can help prevent blood clots from forming between the developing placenta and the uterine wall. Women prescribed this treatment often start early during pregnancy. But more research is needed to determine how long women need to continue injections.

Daily aspirin (81 mg): This also helps with blood clot formation, but there’s no scientific evidence that it’s an effective treatment.

Extra folic acid: Your prenatal vitamin may provide all the folic acid your body needs. But your doctor might advise you to take extra folic acid.

Your doctor might prescribe a prenatal vitamin with L-methylfolate instead of folic acid as some studies have shown that L-methylfolate can decrease the risk of anemia in women with MTHFR gene.

The takeaway

Screening for MTHFR isn’t recommended for every pregnant woman. Many women go on to have normal pregnancies, even if they test positive for the gene. But you may need to be tested if you have a baby born with neural tube defects, or have had multiple miscarriages. Talk to your doctor about your concerns.

CMS Id: 101766