MTHFR and Recurrent Miscarriages

There is never an easy way to deal with miscarriage. It occurs in about 20 percent of all known pregnancies, often within the first trimester. One miscarriage is hard, but when it happens again and again, it can be devastating beyond comprehension. After three or more miscarriages, the condition is known as repeated or recurrent miscarriage or habitual abortion.

Testing for a Reason

Once you have experienced multiple miscarriages, your doctor will likely suggest a battery of specific tests to determine the cause of your recurring loses. The testing is the easy part - the diagnosis can be very difficult because there are times when no answer can be given. Testing will include, along with a complete physical exam and history for both you and your partner;

· genetic testing

· ultrasound

· biopsy of the uterine lining

· hysterosalpingogram (x-ray of the reproductive tract)

· testing for infections in the reproductive organs

· laparoscopy to view the organs

· genetic material testing from previous miscarriages (if available)

· blood work to check hormones, antibodies, and disease

MTHFR DNA Testing - Why It Is Done

One of the blood tests your doctor may order is called MTHFR DNA testing. The formal name for this test is Methylenetetrahydrofolate Reductase Mutations, C677T and A1298C. According to Lab Tests Online, MTHFR reductase is a gene that oversees the production of the MTHFR enzyme, which changes one form of folate into another and is part of the process that converts homocysteine into methionine, an important building block for many proteins. When there is a mutation, it can be heterozygous, which means it occurs on one strand of the chromosome, or it can be homozygous, meaning the mutation is on two strands of the chromosome. This causes an increase in homocysteine levels.

Approximately 10-12 percent of the North American population is homozygous for C677T. The way this plays out in life is that high levels of homocysteine in the blood may contribute to the risk of cardio vascular disease, and thrombosis (inappropriate blood clots). Although there is no clear link between homocysteine and these conditions, the idea that MTHFR mutations may also be a factor in recurrent miscarriages is a consideration for some doctors and researchers. The results of several studies have produced mixed findings with some finding that MTHFR gene variations increase the risk of miscarriages while others cannot find a link. As a result, there are no official recommendations for treatment for women who have MTHFR mutations.

What We Know About MTHFR Gene Mutations

What we do know is that people with MTHFR gene mutations can have a decreased ability to metabolize folic acid and other B vitamins as well. The inability to metabolize folic acid and B vitamins spells trouble for a developing fetus. Babies born to women who are deficient in folic acid and B vitamins are at risk for neural tube defects and other life-threatening situations. It is also known that an elevated level of homocysteine is a potential risk factor for miscarriages because of the increase of blood clots.

Some Doctors Support the Theory ...

The theory in favor of MTHFR gene mutations as a contributor to recurrent miscarriage focuses on the elevated homocysteine levels that result from the mutations. They suggest that because of the increased risk of blood clots, an MTHFR mutation should be treated as a hereditary thrombophilia. Thrombophilia is a disorder that promotes an increase in blood clotting that happens too easily because the body has too many blood clotting factors or too little anti-clotting proteins that limit clot formation. This condition can be inherited or it may develop later in life.

Many doctors believe that hereditary thrombophilias may increase the risk of miscarriage by creating tiny blood clots that inhibit the flow of blood and nutrients to the placenta - and MTHFR gene mutations are included in this group. Yet, the only thrombophilia disorder with a widely accepted treatment is antiphospholipid syndrome, which is the cause of deep vein thrombosis. The link to early recurrent miscarriage is unclear; however, it does go back to the formation of blood clots that block the blood supply to the placenta. Antiphospholipid syndrome is well established as a cause of miscarriage in the later stages of pregnancy, but doctors are not sure what role it plays in early miscarriage.

... And Some Don't

While some doctors test women who have had a miscarriage for MTHFR gene mutations, others don't because they believe the link is not conclusively proven. They will test for homocysteine and recommend therapies to treat elevated levels. Still other doctors do not test for either MTHFR or homocysteine because neither has a formally recommended treatment that can prove it reduces the risk of miscarriage.

As the debate continues, the bottom line appears to be that MTHFR gene mutations come under the heading of "unproven cause of recurrent miscarriage" and the research continues. When it comes to high homocysteine levels in the blood, research is proving that this condition is likely a factor in miscarriages. Perhaps as time goes on the link between homocysteine elevation and MTHFR gene mutation will be established.

Learn more about MTHFR and other possible causes of miscarriage on our site.