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
[{'content': 'Most common cause of primary post-paum hemorrhage is: \nSelect and explain. \nA. Uterine atony, B. Uterine ineia, C. Uterine inversion, D. Retained placenta', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a. Uterine atonyPrimary Postpaum Hemorrhage:Atonic uterus: Uterine atony is most common(80% cases)Grand multiparaOverdistension of the uterus as in multiple pregnancy, hydramnios & big babyUterine fibroidPlacenta: Morbidly adherent placenta(accrete, perceta)Antepaum haemorrhage(both placenta prae & abruption)Prolong labour , Mismanaged 3rd stage labour', 'role': 'assistant'}]