Blood clots aren’t always a bad thing. When you cut yourself, your blood cells are supposed to clump together, which stops blood from leaking to places where it doesn’t belong and kicks off the healing process. But sometimes clots form in places they shouldn’t, and if they occur in a location where blood needs to keep flowing, that can spell trouble.
There are several major types of clots that can cause problems. Clots that block blood to your brain cause stroke, and ones that stop up your heart’s blood flow cause a heart attack. A clot that forms in your leg is called a deep vein thrombosis (DVT). DVTs can break away from their starting place and travel to your lungs. This is called a pulmonary embolism (PE), and can be very serious, even fatal.
Dangerous blood clots are pretty common. In fact, the Surgeon General says 100,000 people die from DVT and PE every year in the U.S. “That’s more than breast cancer and motor vehicle collisions combined, which is staggering,” says Elliot Richard Haut, M.D., Ph.D., co-director of Johns Hopkins Medicine Venous Thromboembolism Collaborative.
While anyone can get a clot in the wrong place at the wrong time, some people may be especially vulnerable—including those who fall into one or more of the following categories.