Am I at Risk of a Blood Clot After Surgery?

Surgery is one of the most significant risk factors for venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE). Published NICE guideline NG89 identifies several factors that increase risk: major surgery (particularly orthopaedic, pelvic, or abdominal), immobility during and after the procedure, active cancer, obesity, previous DVT or PE, dehydration, and use of hormonal contraception or HRT. The risk period extends for several weeks after surgery, not just the immediate post-operative days.

Recognising the symptoms early is important. Published NHS guidance describes DVT symptoms as pain, swelling, warmth and redness — typically in one calf or leg. A pulmonary embolism (PE) (where a clot travels to the lungs) may cause sudden breathlessness, sharp chest pain (often worse when breathing in), and rapid heart rate. Published NICE guidance classifies PE as a medical emergency requiring immediate attention.

Prevention measures recommended by NICE NG89 include early mobilisation (getting up and walking as soon as safely possible after surgery), adequate hydration, compression stockings (TED stockings) where prescribed, and blood-thinning injections (such as enoxaparin/clexane) for patients at higher risk. Continuing prescribed blood thinners for the recommended duration after discharge is important. Published guidance indicates many patients stop early, which increases risk.

Frequently asked questions