This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Which is associated with |ed risk of Thrombo-embolism in a normal pregnancy: \nSelect and explain. \nA. |ed progesterone level, B. |ed production of clotting factors by liver, C. Change in blood viscosity, D. |ed antithrombin III', 'role': 'user'}, {'content': "Answer: B \nExplanation: Stasis, Hypercoagulability and vascular trauma( Virchow's triad) occurs in pregnancy and thus increases the risk of thrombsosis. Hypercoagulability is due to: Increase in Fibrinogen, prothrombin and factors VII,VIII,IX & X Decrease in levels of protein S. Resistance to activated protein C. Increase in levels of antifibrinolytic Types 1 & 2, plasminogen activator inhibitor PAI type 1 & 2. The net result is reduction in the risk of antepaum, intrapaum and postpaum hemorrhage but also a dramatic 10 fold increase in the pregnancy associated thromboembolism.", 'role': 'assistant'}]