Blood Clots in the Leg
A deep vein thrombosis (DVT) is a that occurs in the veins of the lower leg or thigh, usually in the popliteal or femoral vein. Not only can the clot block blood flow, if it breaks off, the clot can travel to the heart, lungs or brain. This condition has the potential to be life threatening. Although most times these clots disappear on their own without complications, some people continue to experience chronic pain and swelling in the affected leg for a long time afterward. Common symptoms of venous thrombosis may include redness and swelling in one leg, pain in the calf when walking or tenderness and increased warmth in the leg. Sometimes a clot can occur without symptoms. Maintaining a healthy weight and getting regular exercise can help to reduce the risk of a blood clot forming in the legs. If you have a history of clotting problems, your doctor may prescribe an anticoagulation drug, more commonly known as a blood thinner.
Estrogen Increases the Risk
Research shows that women who take oral contraceptives over a long period of time can develop blood-clotting disorders. While the hormone estrogen itself does not cause blood clots to form, for women who have a history of thrombosis, the risk rises significantly. Most oral contraceptives contain an estrogen and synthetic progesterone. Even though estrogen increases the levels of clotting factor causing blood to coagulate in the veins, for most women the risk of getting a blood clot is minimal. However, estrogen has the potential to disrupt normal blood flow, causing blood in the veins of the legs to coagulate. This can lead to a blockage that then prevents blood and oxygen from getting to other areas of the body.
Risk Factors
According to reports issued by the National Heart, Lung, and Blood Institute, women who use oral contraceptives have a higher risk of venous thrombosis, particularly if they already show signs of abnormal blood clotting factors. Recent studies show that coagulation problems frequently become apparent during the first year that a woman uses oral contraceptives. Research also suggests that when combined with the use of oral contraceptives, certain protein and antithrombin deficiencies place a woman at increased risk for developing a blood clot in the deep vein of a leg. Despite congenital risk factors such as protein C and protein S deficiency, or prothrombin mutation, the degree of risk varies among women depending on heredity and the number of other risk factors. Naturally, the more risk factors involved, the greater the chance of thrombosis. When there are acquired risk factors at play in addition to the use of oral contraceptives (which contain estrogens absorbed into the bloodstream), the risk increases more.
Deficiencies in Natural Blood Thinners
While a mutation in the prothrombin gene is a hereditary factor found in about 15 percent of those individuals with venous thrombosis, use of oral contraceptives particularly increases the risk for women. Deficiencies in protein C and protein S, or antithrombin affect blood coagulation increasing the risks of both venous thrombosis and pulmonary embolism. Antithrombin is another protein in the blood that acts as a natural blood thinner. Low levels of any of these proteins can cause blood clots to form. Antithrombin deficiency can either be inherited or caused by another disease process in the body.
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