This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thromboembolism and Fat Embolism Syndrome, Subject name: Medicine
[{'content': 'All of the following conditions may predispose to pulmonary embolism except: \nSelect and explain. \nA. Protein S deficiency, B. Malignancy, C. Obesity, D. Progesterone therapy', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Protein S (vitamin K-dependent physiological anticoagulant) acts as a Non-Enzymatic co-factor to activate protein C in the proteolytic degradation of Factor Va and factor Vllla. Decreased (antigen) levels/impaired function (activity) of protein S leads to decrease degradation of factor Va and factor Vllla and an increased propensity to venous thrombosis. Malignancy is a hyper-coagulable state and predisposes to pulmonary embolism. Obesity patients after surgery will be able to mobilize slower and therefore at risk for deep vein thrombosis. Estrogen leads to hyper-coagulable state and not progesterone.', 'role': 'assistant'}]