Every human body has the gene 5-methyltetrahydrofolate. It’s also known as MTHFR.

MTHFR is responsible for the breakdown of folic acid, which creates folate. Some health conditions and 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 affect your pregnancy.

What does the MTHFR gene do?

Hyperhomocysteinemia is a condition where the homocysteine levels are elevated. Hyperhomocysteinemia is often seen in people with a positive MTHFR mutation gene test. High homocysteine levels, especially with low folic acid levels, can lead to pregnancy complications that include:

  • miscarriage
  • preeclampsia
  • birth defects

Folate is responsible for:

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

When the MTHFR gene malfunctions, folic acid isn’t broken down. This is known as a mutated MTHFR gene. It’s not uncommon to have a mutated gene. In the United States, it’s estimated that around 25 percent of people who are Hispanic and up to 15 percent of people who are white have this mutation, according to the Genetic and Rare Diseases Information Center.

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 anencephaly
  • 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 pregnancy 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. This is 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. This is 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. This is 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 your doctor may order this test if you’ve:

  • had multiple miscarriages
  • have a family history of mutated MTHFR gene
  • had genetic issues with another pregnancy

Results are usually available in one to two weeks.

To check for a MTHFR gene mutation, variants of the MTHFR gene are tested. The two most common gene variants tested are called C677T and A1298C. If a person has two of the C677T gene variants, or a C6771 gene variant and one A1298C gene variant, the test often shows elevated homocysteine levels.

But two A1298C gene variants usually aren’t associated with elevated homocysteine levels. It’s possible to have a negative MTHFR gene test and have high homocysteine levels.

Positive mutated MTHFR gene treatment options

Treatment for the positive MTHFR gene mutation is still being studied. However, many doctors will prescribe treatment 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 milligrams). This also helps with blood clot formation, but there’s no scientific evidence that it’s an effective treatment.
  • Prenatal vitamin with L-methylfolate. Your doctor might prescribe this instead of folic acid. Some studies have shown that L-methylfolate can decrease the risk of anemia in pregnant women.

The takeaway

Screening for MTHFR mutation isn’t recommended for every pregnant woman. Many women go on to have normal pregnancies, even if they test positive for the gene mutation. 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.