This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrine, Subject name: Pharmacology
The mechanism by which ergometrine stops postpaum hemorrhage is that it: 
Select and explain. 
A. Causes vasoconstriction of uterine aeries, B. Increases tone of uterine muscle, C. Promotes coagulation, D. Induces platelet aggregation
B: Increases tone of uterine muscle
Answer: B: Increases tone of uterine muscle 
Explanation: All drugs used in PPH including oxytocin, misoprostol and ergometrine cause uterine contraction. The blood vessels are pressed in the uterine muscle and bleeding stops Indications to sta oxytocin Post paum hemorrhage Uterine ineia Breast engorgement due to abnormal milk ejection reflex