Deep vein thrombosis (DVT) is a blood clot in one of the major deep veins, usually of the lower legs, thighs, or pelvis. A clot blocks blood circulation through these veins, which carries blood from the lower body back to the heart. The blockage can cause pain, swelling, or warmth in the leg. Blood clots in the veins can cause inflammation called thrombophlebitis. If the clot breaks loose and travels through the bloodstream, it can block a blood vessel in the lungs. Called pulmonary embolism, this can lead to severe trouble breathing and even death.
In the U.S., between 300,000 and 600,000 people per year get deep vein thrombosis. About 100,000 people die each year from pulmonary embolism.
Being obese makes you more likely than people of normal weight to get a blood clot deep in a vein.
The primary danger of this deep-vein thrombosis, or DVT, is that the clot, usually in the leg, can dislodge and travel to the lungs, causing a serious blockage known as a pulmonary embolism, or PE.