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: Gynaecology & Obstetrics
The sensitivity of uterine musculature is 
Select and explain. 
A. Enhanced by progesterone, B. Enhanced by estrogen, C. Inhibited by estrogen, D. Enhanced by estrogen and Inhibited by progesterone
D: Enhanced by estrogen and Inhibited by progesterone
Answer: D: Enhanced by estrogen and Inhibited by progesterone 
Explanation: Progesterone reduces muscle excitability by increasing calcium binding, thereby reducing free intracellular calcium. Oestrogen has the opposite effect and increases myometrial excitability.Refer page no 106 of Textbook of obstetrics, Sheila Balakrishnan, 2 nd edition.