Anyone–at any age, at any time–can develop a blood clot. However, certain factors can increase the risk of developing deep vein thrombosis (DVT).

• Prolonged immobility:  The contraction of the calf muscle in the leg helps to keep blood circulating. When the leg remains still for long periods of time, the calf muscles aren’t contracting to help blood circulate and a blood clot can form. Any situation where your legs remain still for long periods of time can increase clotting risk—such as when sitting on long air flights, driving on a long car trip, working behind a desk for hours or sitting immobile for long periods while surfing the internet or playing video games. Prolonged bedrest–such as with a hospital stay or other paralysis–also increases clotting risk.
• Surgery or injury:  Injury to the veins–due to either surgery or trauma–can slow the flow of blood and increase the risk of developing clots.
• Clotting disorder:  Some individuals have a medical condition where the blood tends to clot more easily. This is known as thrombophilia, and it can be either inherited (genetically passed down from your parents) or acquired (related to a transient or temporary cause).
• Estrogen:  Oral contraceptives (birth control pills) and hormone replacement therapy (HRT) contain estrogen, which can increase the blood’s ability to clot.
• Pregnancy:  During pregnancy, hormonal changes increase the blood’s ability to clot. Pregnancy also increases pressure on the veins in the hip and leg area, which can restrict blood flow, increasing the risk of a blood clot forming. The risk of blood clots from pregnancy remains increased for about six weeks following birth of the baby. Pulmonary embolism (a clot which breaks off and travels to the lung) is the leading cause of maternal death in the United States.
• Obesity:   Being overweight increases the risk for developing a blood clot.
• Smoking:  Smoking affects circulation and increases the risk for developing a blood clot.
• Cancer:  Some forms of cancer and cancer treatment increase the tendency of the blood to clot.
• A previous DVT or PE:   If you’ve had deep vein thrombosis in the past, you are more likely to have a future clot.

If you think you may be at risk for developing a blood cot, talk with your doctor. Make sure your doctor is aware of all medications you are taking and any family history of blood clots or clotting disorders.

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