Homocysteine and Recurrent Miscarriage - Is There a Link?

Elevated Levels of This Amino Acid Cause Some Pregnancy Complications

Doctor and Patient, Abdomen Palpation
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Your doctor may check your homocysteine level if you've had recurrent miscarriages, and you might be wondering what this test is for. Homocysteine is a type of amino acid that is naturally found in the body that may be related to miscarriage risk.

Homocysteine is not harmful at normal levels, but when levels of homocysteine are too high, pregnancy-related problems can result. Some researchers have found correlations between high homocysteine and risk of miscarriage.

High Homocysteine and Miscarriage

Elevated homocysteine is not yet proven to cause miscarriage - researchers are still investigating the link.

If there is a relationship, the most likely explanation is that high homocysteine causes a condition called hypercoagulability where the blood clots more easily. This could cause that tiny blood clots to block blood vessels in the placenta, leading to miscarriage. This scenario would be similar to another common cause of miscarriages, antiphospholipid syndrome.

Other Pregnancy Complications

Elevated homocysteine is a confirmed risk factor for these problems in pregnancy:

As with miscarriage, the evidence is conflicting on whether high homocysteine levels cause other pregnancy problems:

How Your Genes May Play a Role

If you have high homocysteine levels, your genetics may be a cause.

People who have variations in the MTHFR gene, especially the C677T variation, are more likely to have high homocysteine levels. And some studies have found a correlation between MTHFR gene variants and increased miscarriage risk.

The leading theory behind the association is that high homocysteine levels in people with MTHFR gene variants pose a miscarriage risk.

Some doctors test for MTHFR gene variants as a part of the recurrent miscarriage testing workup. Others feel it is more valuable to test for homocysteine because not everyone with MTHFR gene variants will have high levels of the amino acid.

What Else Causes High Homocysteine?

MTHFR gene variants are not the only cause of high homocysteine. Your body uses the nutrients folic acid, vitamin B6 and vitamin B12 to metabolize, or use up, homocysteine. People who are deficient in those vitamins can have high homocysteine levels. A variety of underlying health conditions and medications may also be related to high homocysteine levels.

The Other Health Risks

Research is conflicted on exactly what role high homocysteine plays in long-term health. Some studies have found that high homocysteine correlates with the risk of developing heart disease and neurological problems.

Treating Elevated Homocysteine In Recurrent Miscarriages

There are no formal recommendations to check homocysteine levels in women with recurrent miscarriages. There's also no universally recommended treatment protocol for handling elevated homocysteine levels in women who are found to have them.

Some doctors, however, do test homocysteine (or MTHFR gene variants) in women with recurrent pregnancy loss and recommend treatment even in the absence of formal recommendations. The usual recommendation in women with elevated homocysteine levels is to take high doses of folic acid and B vitamins to improve the body's metabolism of homocysteine.

A few doctors may recommend anticlotting therapy, such as heparin or low-dose aspirin, in order to prevent blood clots from forming during pregnancy, but this practice is not standard.


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