This information is intended for members of the public in UK only.

What causes a VTE?

Anyone can develop a VTE, but some things increase the risk of it occurring. For example, injury from trauma or surgery triggers the body’s natural clotting process, as do high levels of the hormone oestrogen and smoking. The more of these risk factors you have the greater the chance of having a VTE.

Deep vein thrombosis (DVT) is generally caused by a combination of underlying medical conditions or situations that increase the chances of it occurring:

  • Slow blood flow due to lack of mobility because of:
    • Severe medical illness
    • Hospitalisation
    • Prolonged bed rest (more than 3 days)
    • Long-haul travel (involving sitting for longer than 4 hours)
    • Sedentary lifestyle.
  • A tendency for blood to clot quickly due to:
    • Inherited conditions
    • Increased oestrogen levels:
    • Pregnancy and up to 6 weeks after birth
    • Hormone replacement therapy and combined oral contraceptives
  • Injury or inflammation recent surgery (Within 3 months)
    • Certain chronic illnesses:
    • Heart, lung or kidney disease
    • Cancer and its treatments
  • Other factors:
    • Personal history of clotting problems or previous DVT/PE
    • Family history of DVT/PE
    • Increasing age (over 40 years)
    • Smoking
    • Being overweight or obese.
patient in hospital with nurse image

Reference information

This section contains reference information only, is general in nature and intended to provide a general overview of venous thromboembolism for the general public in the UK. It is not intended to replace in any way the opinion of a healthcare professional. For specific information about this pathology and/or detection, diagnosis, prognosis, administration and, where applicable, appropriate treatment for each specific case, please promptly consult a healthcare professional. The use of this website is subject to the legal notice, the privacy and cookie policy, and the applicable laws and regulations.