What Are the Causes of Bloodclots?

A blood clot is a solid mass of blood cells that inhibit blood flow through the body. Blood clots are potentially dangerous to the health because they can move throughout the body and obstruct blood flow to the lungs. The simple answers to what causes a blood clot are two: the blood does not flow properly or has difficulty clotting. The reasons for these are many and depend on each person's family and medical histories, and overall health.

Blood Clotting Disorders

Hereditary blood clotting disorders may cause blood clots or increase the risk in some people, according to the medical team at the University of Michigan Health System. Having abnormalities such as factor V Leiden, lupus anticoagulants, or deficiencies of proteins S or C can cause blood clotting irregularities. Blood clots in the lungs or legs are also more likely in people who have a family history of deep vein thrombosis or pulmonary embolism.

Lack of Movement

Being sedentary for long periods of time can increase the risk of developing a blood clot. Walking or just moving about normally causes the calf muscles in the legs to contract, which promotes circulation. Getting up for a few minutes for every half hour of sitting (or standing still) can help prevent the formation of blood clots. People who are bedridden should ask their doctors about exercises they can do to lower their risks.

Trauma

Trauma to the veins, whether by an accidental injury or through the normal procedures for surgery, may cause blood clots in some people, reports the Mayo Clinic. Veins that have been dilated are more likely to develop pooling of the blood, which can lead to abnormal clotting.

Hormonal Changes

Hormonal changes can affect circulation and may lead to blood clots. Women who use oral contraceptives for birth control or hormone replacement therapy after menopause may be more susceptible to blood clots. Pregnancy can also pose a risk due to the added pressure put on the expectant mother's calves.

Circulatory Problems

Blood clots can be caused by certain health issues that interfere with normal circulation. Smoking and being overweight are two factors affecting both circulation and blood clotting that can be remedied by lifestyle changes. Heart disease and heart failure may also lead to blood clots because the blood flow is abnormal.