A blood clot (also called a thrombosis) is a mass or clump of blood that forms when blood changes from a liquid to a solid. The body normally makes blood clots to stop the bleeding after a scrape or cut. But sometimes blood clots can partly or completely block the flow of blood in a blood vessel, like a vein or artery. This can cause damage to body organs and even death. Blood clots affect 900,000 people each year and as many as 100,000 people die each year due to blood clots.
Risk factors for blood clots
Certain conditions make you more likely to have a blood clot. These include:
- Being pregnant. Your blood clots more easily during pregnancy to help your body get ready to lessen blood loss during labor and birth. Also, blood flow in your legs gets slower late in pregnancy. This is because the blood vessels around your pelvis and other places are more compressed (narrow) and your growing uterus (womb) puts pressure on your pelvis.
- Having certain health conditions, like a thrombophilia, high blood pressure, diabetes or being overweight or obese. A family history of blood clotting problems also increases your chances of blood clots. If you have a family history or a personal history of a thrombophilia, make sure you tell your health care provider.
- Taking certain medicines, like birth control pills or estrogen hormones. These medicines can increase the risk of clotting. If you’ve had problems with blood clots or thrombophilias or have a family history of these conditions, birth control pills may not be safe for you to use. Talk to your health care provider about other birth control options.
- Smoking. Smoking damages the lining of blood vessels, which can cause blood clots to form.
- Having surgery, like a cesarean section. The American College of Obstetricians and Gynecologists (ACOG) recommends that doctors help prevent blood clots in women during a c-section. This may include using devices that put pressure on your legs to help keep your blood flowing during the c-section, like compression socks.
- Being dehydrated. This means you don’t have enough water in your body. Dehydration causes blood vessels to narrow and your blood to thicken, which makes you more likely to have blood clots.
- Not moving around much. This may be because you’re on bed rest during pregnancy or recovering from surgery. Being still for long periods of time can lead to poor blood flow, which makes you more likely to have blood clots. Even sitting for long periods of time, like when travelling by car or plane, can increase your chances of having a blood clot.
- Having a baby. You’re more likely to have a blood clot in the first 6 weeks after birth than women who haven’t given birth recently.
Know the signs
Make sure you recognize the symptoms of a blood clot. These include:
- Swelling, usually in one leg (or arm)
- Leg pain or tenderness often described as a cramp or Charley horse
- Reddish or bluish skin discoloration
- Leg (or arm) warm to touch
If you have any signs or symptoms, contact your health care provider right away. Blood clots can be treated with special medications.
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