The abbreviation DVT/PE refers to a VTE where a deep vein thrombosis (DVT) has moved to the lungs (PE or pulmonary embolism).

[23] 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.

[24] In contrast to the understanding for how arterial thromboses occur, as with heart attacks, venous thrombosis formation is not well understood.

[7] The process is thought to be initiated by tissue factor-affected thrombin production, which leads to fibrin deposition.

Due to the blood flow pattern, the base of the valve sinus is particularly deprived of oxygen (hypoxic).

Stasis exacerbates hypoxia, and this state is linked to the activation of white blood cells (leukocytes) and the endothelium.

Hypoxia also causes reactive oxygen species (ROS) production that can activate HIF-1, EGR-1, and nuclear factor-κB (NF-κB), which regulates HIF-1 transcription.

[33] In hospitalized people who have had a stroke and not had surgery, mechanical measures (compression stockings) resulted in skin damage and no clinical improvement.

[30] The American College of Physicians (ACP) gave three strong recommendations with moderate quality evidence on VTE prevention in non-surgical patients: In adults who have had their lower leg casted, braced, or otherwise immobilized for more than a week, LMWH may decrease the risk and severity of deep vein thrombosis, but does not have any effect on the incidence of pulmonary embolism.

[36] The American Society of Hematology strongly suggests that people undergoing chemotherapy for cancer who are at low risk of a VTE avoid medications to prevent thrombosis (thromboprophylaxis).

[37] For people undergoing chemotherapy for cancer that do not require a hospital stay (those undergoing ambulatory care), there is low certainty evidence to suggest that treatment with direct factor Xa inhibitors may help prevent symptomatic VTEs, however this treatment approach may also lead to an increase in the risk of a major bleed compared to a placebo medication.

[38] For people who are having surgery for cancer, it is recommended that they receive anticoagulation therapy (preferably LMWH) in order to prevent a VTE.

[40][39] Specifically for patients with various types of lymphoma, there is a risk assessment model, ThroLy, to help providers determine how likely a thromboembolic event is to occur.

[42] In the UK, guidelines by the National Institute for Health and Care Excellence (NICE) were published in 2012, updated in 2020.

[44] LMWH is usually administered by a subcutaneous injection, and a person's blood clotting factors do not have to be monitored as closely as with UFH.

USA recommendations for those without cancer include anticoagulation (medication that prevents further blood clots from forming) with the DOACs dabigatran, rivaroxaban, apixaban, or edoxaban rather than warfarin or low molecular weight heparin (LMWH).

[43] For long-term treatment in people with cancer, LMWH is probably more effective at reducing VTEs when compared to vitamin K antagonists.

[46] While topical treatments for superficial venous thrombosis are widely used, the evidence is strongest for the heparin-like drug fondaparinux (a factor Xa inhibitor), which reduces extension and recurrence of superficial venous thrombosis as well as progression to symptomatic embolism.