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 40 weeks pregnant developed postpaum hemorrhage due to uterine atony. Which of the following drug can be given to this patient to stop the bleeding? 
Select and explain. 
A. Oxytocin, B. Methergine, C. Progesterone, D. Prostaglandins
B: Methergine
Answer: B: Methergine 
Explanation: Ergot alkaloids markedly increase the motor activity of the uterus. Although their capacity to induce sustained uterine tetany precludes their use in the induction or facilitation of labor, they are used to prevent or treat postpaum hemorrhage in normotensive women. In this setting, the preferred ergot alkaloids are ergonovine or its methyl analog methylergonovine (methergine). They are administered intramuscularly or intravenously, exhibit rapid onsets of action, and their effects persist for 45 minutes to 3 hours depending on the route of administration. Adverse effects include nausea and vomiting, elevated blood pressure, and decreased pain threshold requiring analgesia. Ref: Schimmer B.P., Parker K.L. (2011). Chapter 66. Contraception and Pharmacotherapy of Obstetrical and Gynecological Disorders. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e.