Deep Vein Thrombosis (DVT) is a blood clot in a deep vein, often in the legs. These clots can block blood flow and, if dislodged, may cause a life-threatening pulmonary embolism in the lungs. Understanding DVT risk factors is important for prevention and early recognition. Awareness helps individuals discuss their risk with healthcare providers for proactive health management.
Medical Conditions and Treatments
Medical conditions and treatments can increase DVT risk. Cancer increases DVT risk due to pro-clotting substances from tumors and treatments like chemotherapy or radiation, which can damage blood vessels. Heart failure slows blood flow, especially in the legs, promoting clot formation. Inflammatory bowel diseases (Crohn’s, ulcerative colitis) involve chronic inflammation that can activate clotting.
Kidney disease, especially nephrotic syndrome, can cause loss of natural anticoagulant proteins, disrupting clotting balance. Autoimmune diseases like lupus also cause inflammation that can damage blood vessels and promote abnormal clotting. Major surgeries, particularly hip or knee replacements, pose a high risk due to immobility and direct vessel trauma. A personal history of DVT or pulmonary embolism increases recurrence risk. Central venous catheters, used for long-term medication, can irritate vein walls and lead to localized clots.
Lifestyle and Situational Influences
Lifestyle and situational factors can also increase DVT risk. Prolonged immobility, like long travel or bed rest, slows leg blood flow, allowing pooling and clotting. Obesity increases DVT risk by raising vein pressure and promoting inflammation that affects clotting. Smoking damages blood vessel linings, making them prone to clots and increasing blood viscosity.
Advanced age, typically over 60, increases risk as vein elasticity decreases and blood flow becomes less efficient. Pregnancy and the postpartum period are high-risk due to uterine pressure on pelvic veins, increased blood volume, and hormonal changes that promote clotting; this risk extends up to six weeks after childbirth. Hormonal birth control and hormone replacement therapy (estrogen-containing) can increase blood’s clotting tendency. Trauma or injury, like a bone fracture or severe muscle damage, can directly injure blood vessels and trigger clotting. Dehydration can also increase blood viscosity, making it thicker and more likely to clot.
Inherited and Genetic Predispositions
Genetic factors can predispose individuals to DVT, even without other apparent risk factors. One common inherited condition is Factor V Leiden mutation, where a genetic change makes Factor V (a clotting protein) resistant to inactivation by Protein C (a natural anticoagulant). This resistance prolongs clotting, increasing clot formation. Similarly, the Prothrombin gene mutation (G20210A) results in higher prothrombin levels, increasing blood’s clotting tendency.
Deficiencies in natural anticoagulant proteins also raise DVT risk. Antithrombin deficiency means insufficient antithrombin, a protein that regulates clotting by inactivating clotting factors. Protein C or S deficiencies also impair clotting regulation, as these proteins inactivate Factor V and Factor VIII. A family history of DVT suggests an inherited predisposition, as these genetic variations can be passed down. Such predispositions can alter the balance of clotting and anti-clotting proteins.
References
Mayo Clinic. Deep vein thrombosis (DVT). Available at: https://www.mayoclinic.org/diseases-conditions/deep-vein-thrombosis/symptoms-causes/syc-20352557. [Accessed: 2025-07-26].