<unk>  thrombi are caused mainly by a combination of<unk>  stasis and hypercoagulability—but to a lesser extent endothelial damage and activation. The three factors of stasis, hypercoagulability, and alterations in the blood vessel wall represent Virchow's triad, and changes to the vessel wall are the least understood. Various risk factors increase the likelihood of any one individual developing a thrombosis. Risk factors Acquired * Older age * Major surgery, orthopedic surgery, neurosurgery * Cancers, most particularly pancreatic, but not cancers of the lip, oral cavity, and pharynx * Immobilization, as in orthopedic casts, the sitting position, and travel, particularly by air * Pregnancy and the postpartum period * Antiphospholipid syndrome (such as lupus anticoagulant) * Trauma and minor leg injury * Previous<unk> E * Oral contraceptives * Hormonal replacement therapy, esp. oral * Central<unk>  catheters * Inflammatory diseases/some autoimmune diseases * Nephrotic syndrome * Obesity * Infection * HIV * Myeloproliferative neoplasms including essential thrombocytosis and polycythemia vera * Chemotherapy * Heart failure Inherited * Antithrombin deficiency * Protein C deficiency * Protein S deficiency (type I) * Factor V Leiden * Prothrombin G20210A * Dysfibrinogenemia * Non O-blood type Mixed * Low free protein S * Activated protein C resistance * High factor VIII levels * Hyperhomocysteinemia * High fibrinogen levels * High factor IX levels * High factor XI levels The overall absolute risk of<unk>  per 100,000 woman years in current use of combined oral contraceptives is approximately 60, compared to 30 in non-users. The risk of thromboembolism varies with different types of birth control pills; Compared with combined oral contraceptives containing levonorgestrel (LNG), and with the same dose of estrogen and duration of use, the rate ratio of deep vein thrombosis for combined oral contraceptives with norethisterone is 0.98, with norgestimate 1.19, with desogestrel (DSG) 1.82, with gestodene 1.86, with drospirenone (DRSP) 1.64, and with cyproterone acetate 1.88.<unk>  thromboembolism occurs in 100–200 per 100,000 pregnant women every year. Regarding family history, age has substantial effect modification. For individuals with two or more affected siblings, the highest incidence rates is found among those ≥70 years of age (390 per 100,000 in male and 370 per 100,000 in female individuals), whereas the highest incidence ratios compared to those without affected siblings occurred at much younger ages (ratio of 4.3 among male individuals 20 to 29 years of age and 5.5 among female individuals 10 to 19 years of age).
Venous thrombosis
Migraine
Deep vein thrombosis
Venous ulcer
Thrombophlebitis
Phlebitis
Thrombosis
Lymphangitis