Blood clots form when certain parts of your blood thicken, forming a semisolid mass. This process may be triggered by an injury or it can sometimes occur inside blood vessels that don't have an obvious injury.

Once these clots form, they can travel to other parts of your body, causing harm. Factors and conditions that can cause troublesome blood clots, as well as serious conditions that are associated with blood clots, include:

  1. Antiphospholipid syndrome
  2. Arteriosclerosis / atherosclerosis
  3. Certain medications, such as oral contraceptives and hormone therapy drugs
  4. Coronavirus disease 2019 (COVID-19)
  5. Deep vein thrombosis (DVT)
  6. Factor V Leiden
  7. Family history of blood clots
  8. Heart arrhythmia (heart rhythm problems)
  9. Heart attack
  10. Heart failure
  11. Obesity
  12. Peripheral artery disease (PAD)
  13. Polycythemia vera
  14. Pregnancy
  15. Prolonged sitting or bed rest
  16. Pulmonary embolism — a blood clot in an artery in the lung.
  17. Smoking
  18. Stroke
  19. Surgery

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

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Feb. 25, 2021