(HealthDay News) -- Blood clots can dissolve on their own, but don't always.
Deep vein thrombosis (DVT)is a type of clot that tends to form in a major vein of the leg, although it can form in other parts of the body, too.
The clot ultimately can travel through the heart to the lungs, where it can cause a life-threatening condition called a pulmonary embolism.
The American Society of Hematology says roughly 900,000 people in the United States develop a DVT each year, resulting in 100,000 deaths.
The group says these factors raise a person's risk of developing a blood clot:
- Oral contraceptives.
- Certain surgeries.
- A family history of clots.
- Chronic inflammatory disease.
- High blood pressure.
- High cholesterol.