This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
A reduction in which of the following clotting factors is consistent with normal pregnancy? 
Select and explain. 
A. Fibrinogen, B. Factor XIII, C. Factor VIII, D. Factor X
B: Factor XIII
Answer: B: Factor XIII 
Explanation: Clotting factors that decrease during pregnancy are factor XI and XIII. Clotting factors increase during pregnancy are X, IX, VIII, VII, and II. Fibrinogen level is raised by 50% from 200-400 mg% in non-pregnant to 300-600 mg% in pregnancy. Ref: Dutta, 6th ed, Page 52