Blood clots can affect anyone and may lead to significant health problems, but some people are at higher risk for life-threatening blood clots.
One in four people worldwide die of conditions caused by blood clots, also known by the medical term “thrombosis.” In fact, thrombosis is the third leading vascular diagnosis after heart attack and stroke, according to the American Heart Association.
There are two types of life-threatening blood clots, also called venous thromboembolism (VTE). Deep vein thrombosis, or DVT, is a clot in a deep vein in the leg, arm or other large veins. A pulmonary embolism, or PE, occurs when a clot breaks free and travels to the lungs, blocking some or all of the blood supply.
Although VTE can be fatal, many, if not most, cases are preventable. Talk with a health care provider to understand your risk and use this information from the American Heart Association to understand the circumstances that may lead to higher risk:
Extended travel: Traveling longer than 8 hours, whether by plane, car, bus or train, can increase risks for life-threatening blood clots. Being seated for long periods can slow blood flow, and high altitudes can activate the body’s blood-clotting system. Consider wearing compression socks or finding time to stretch or walk around when traveling to aid in proper blood flow.
Estrogen-based birth control: Estrogen-based contraceptives can increase the risks for a life-threatening blood clot. Risks are present whether the estrogen is delivered into the blood stream with pills, a patch, an injection or a vaginal ring contraceptive. The risk is highest when first starting these prescriptions as the hormonal changes can cause blood cells to bind together more readily. Taking estrogen contraceptives can increase risks if you have factors such as inherited blood-clotting disorders, a family history of blood clots, surgery, obesity or plans for prolonged travel.
Recent hospital stays: Roughly 50 percent of life-threatening blood clots happen within three months of a hospitalization, surgery or traumatic injury, though only one in four adults knows that hospitalization is a risk factor for VTE. Hospital patients at the greatest risk are those with limited ability to move, people with previous history of blood clots, patients age 60 and older, people who have abnormal blood-clotting conditions and patients who have spent time in an intensive care or coronary care unit.
Pregnancy and childbirth: Pregnant women are at four times greater risk of a life-threatening blood clot than non-pregnant women. The risk increases after delivery. Blood clots cause approximately 10 percent of all maternal deaths in the United States, with pulmonary embolism being the leading cause. The blood-clotting system is activated during pregnancy to protect the woman from fatal bleeding during labor and delivery. In addition, the growing baby presses on the veins of the pelvis, slowing blood flow. Other risk factors for a blood clot during pregnancy and childbirth include inherited blood-clotting disorders, a history of blood clots, older age at the time of pregnancy, obesity, cesarean delivery and major bleeding after delivery.
Cancer diagnosis: Cancer patients typically spend significant time in the hospital which often means they are lying still for long periods and are more likely to have surgery or receive chemotherapy, which also increases risks. Cancers in bones, ovaries, the brain or pancreas and lymph nodes are associated with the highest incidence of a life-threatening blood clot.
If you have concerns about your risk for blood clots, especially if you have multiple risk factors, consult with your health care provider about how to lower the risk. Learn more at heart.org/bloodclotrisk.
American Heart Association