Blood clots may include venous thromboembolism (deep vein thrombosis and pulmonary embolism), anaphylaxis. Risk factors include deep vein thrombosis, recent surgery, cancer, and previous thromboembolism. Risks of therapy include death, myocardial infarction, stroke, venous thromboembolism, and tumor recurrence. Clozapine is also associated with thromboembolism (including pulmonary embolism), myocarditis, and cardiomyopathy. Together, deep vein thrombosis and PE are known as venous thromboembolism (VTE). Other risks include stroke and venous thromboembolism. Treatment with fondaparinux reduces the risk of subsequent venous thromboembolism. It typically causes transient embolism similar to thromboembolism but of shorter duration. During pregnancy, high levels of estrogens increase coagulation and the risk of venous thromboembolism. Contraindications of progestogens may include breast cancer and a history of venous thromboembolism among others. Anticoagulants are used when venous thromboembolism is present. Some people have a higher risk of developing thrombosis and its possible development into thromboembolism. CMA does not increase the risk of venous thromboembolism. Hypertension and atherosclerosis are risk factors for both atherosclerotic plaques and thromboembolism. Approaches to prevent venous thromboembolism (VTE) are performed both before and after surgery.