This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Anatomy
Most common cause of postpaum hemorrhage is: 
Select and explain. 
A. Uterine atony, B. Retained products, C. Trauma, D. Bleeding disorders
A: Uterine atony
Answer: A: Uterine atony 
Explanation: Most common cause of primary postpaum hemorrhage is Atonic uterus Most common cause of secondary postpaum hemorrhage is Retained placenta Ref: Datta Obs 9e pg 393.