Who’s most at risk of developing blood clots?

Blood clots. Those two words can be scary, especially after a flight or car ride when you’ve been sitting for a long time and then, shortly after, your leg starts to hurt, and you wonder, “Is this what a blood clot feels like?”

To better understand blood clots and how likely you are to develop one, it’s important to know what causes them. Blood clots form when the flow of blood in a vein slows down or damage occurs to a vein and prevents your blood from circulating properly.

When blood clots occur in deep veins, such as those in your legs, it’s called deep vein thrombosis (DVT). If the clot breaks loose and travels to your brain, it can cause a stroke. If the clot travels to your lungs, it can cause a pulmonary embolism (PE). This can be a very serious condition because you can die if the flow of blood and oxygen is blocked.

Classic symptoms for DVT include pain, swelling, discoloration (bluish or reddish) and warmth. For PEs, symptoms include shortness of breath, chest pain, lightheadedness, rapid pulse, an unexplained cough – perhaps even coughing up blood.

Common risk factors include obesity, pregnancy, increase in estrogen (such as birth control pills or hormone replacement therapy), smoking, sitting for a long period of time (especially with your legs crossed) or lying in bed for a long time with your legs still. Blood clots can also form after major surgery or if you’ve injured a vein from a broken bone or a severe muscle injury.

If someone in your family has had a stroke, heart attack or any type of blood clot, this also can mean you are at higher risk for having clots and should talk with your doctor about it.

To reduce your risk for dangerous blood clots, health care providers offer several suggestions.

“Get active,” says Dr. Sameena Jawed, an Advocate Medical Group family medicine physician at Advocate Good Shepherd Hospital in Barrington, Ill. “Make sure to exercise regularly and avoid sitting still. If you are sitting for a long time during travel in a plane or car, don’t cross your legs and try to stand or walk when you can. Losing weight and quitting smoking can also help you avoid blood clots.”

Sometimes, physicians prescribe blood thinners, also known as anticoagulants, to treat or prevent blood clots. The most common anticoagulant used is warfarin, which requires a patient to undergo regular blood testing to ensure the dosage is safe and effective. There are some newer medications that don’t require blood testing but do require other lab monitoring to make sure organs like the kidneys and liver are continuing to function properly.