Heparin Therapy

Definition - What does Heparin Therapy mean?

Heparin therapy is used to thin blood in women with recurrent pregnancy loss (RPL) or those with an autoimmune problem, such as antiphospholipid antibody syndrome (APS). RPL is defined as 2 or more consecutive fetal losses, most often occurring in the first 3 months of pregnancy.

Outside the context of fertility, heparin is used to treat and prevent heart attacks, stroke, and clots in veins, as well as before and after surgeries. There are two types of heparin: Unfractionated heparin (UFH) and low molecular weight heparins (LMWH). Owing to fewer side effects and more effective results, LMWH is preferred over UFH for RPL and APS.

FertilitySmarts explains Heparin Therapy

RPL is a common health issue affecting around 1% to 5% of women during the reproductive years with the cause of about 68% of recurrent pregnancy loss being unknown. There are a variety of causes of RPL. These include:

  • Chromosomal abnormalities
  • Uterine abnormalities
  • Thrombophilias such as APS, protein S and protein C deficiency
  • Immunological condition like lupus

Heparin is usually used with low-dose aspirin for treating women with RPL secondary to antiphospholipid antibodies. This is because of the increased tendency of the blood to clot in women with APS. This condition also affects the vessels of the placenta and uterus, making it difficult for the pregnancy to continue. Being a blood thinner, heparin prevents and/or treats these clots. It has shown to be promising at allowing a pregnancy to reach full-term, thereby improving the live birth rates in women with APS by about 85%.

The benefits of heparin with low-dose aspirin therapy are usually seen in RPL due to antiphospholipid antibody syndrome and not in unexplained miscarriages. This effect of heparin therapy, is, however, controversial. According to some experts, heparin may boost the odds of pregnancy even in women with recurrent miscarriages without an obvious cause.

The use of LMWH in the first 3 months of pregnancy appears to be safe for both the mother and baby, with significantly reduced episodes of bleeding. While the risk of bleeding is low with LMWH, it still needs monitoring. The doctors monitor response to LMWH with a blood test, called anti-factor Xa. LMWH blocks the clotting cascade by blocking the activity of the activated form of clotting factor X, and thus, prevents the blood from clotting.

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