What is the most common cause of DVT?

Deep vein thrombosis is a clot in a vein, usually in the leg. Sitting still for a long journey, staying in bed after illness or surgery, and wearing a cast can reduce the calf-muscle pumping that helps blood return to the heart. Previous clots, pregnancy, some medicines, cancer, smoking, and inherited clotting disorders can add to the risk. A leg clot may cause one-sided swelling, warmth, tenderness, or a change in colour, but some clots cause few symptoms.

New swelling or pain in one leg should be assessed promptly, especially after travel, an operation, or a period in bed. Do not massage the area or start blood-thinning medicine without medical advice. A clinician may examine the leg and arrange tests such as an ultrasound. Keep moving regularly during long periods of sitting, drink normally, and follow movement instructions after surgery.

Call emergency services immediately for sudden breathlessness, chest pain that worsens with breathing, coughing blood, fainting, or a very fast heartbeat. These can signal that a clot has travelled to the lungs. Seek same-day medical care for unexplained one-sided leg swelling, warmth, or tenderness, even if breathing is normal.

Ask what may have slowed your circulation, whether you need an ultrasound, how long treatment may last, and which activities are safe while you recover. Mention recent travel, surgery, pregnancy, medicines, and any personal or family history of clots.