This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Normal Menstruation, Abnormal Menstruation, Menopausal Physiology and forsight of conception, Subject name: Gynaecology & Obstetrics
[{'content': 'Which of the following treatment for menorrhagia is not suppoed by evidence? \nSelect and explain. \nA. Ethamsylate, B. Tranexamic acid, C. OCP, D. Progesterone therapy on days 5 -25', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ethamsylate is known to reduce capillary fragility. Hence it is not effective for uterine bleeding which is more due to the vasodilator prostaglandins. Antiprostaglandins are used since NSAIDs reduce prostaglandin levels by inhibiting cyclooxygenase and decreasing the ratio of prostacyclin to thromboxane. Prostaglandin E2 synthesis Prostaglandin E binding sites are reduced as well.', 'role': 'assistant'}]