This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Natural Methods, Barrier Methods, IUDs, OCPs, Subject name: Social & Preventive Medicine
[{'content': 'Mifepristone used for inducing aboion acts on: \nSelect and explain. \nA. Hypothalamo-pituitary Ovarian axis, B. Uterine contractility, C. Progesterone receptors, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Mifepristone, also known as RU-486, is a medication typically used in combination with misoprostol to bring about an aboion during pregnancy. This combination is 97% effective during the first 63 days of pregnancy. It is also effective in the second trimester of pregnancy. Mifepristone blocks a natural substance progesterone that is needed for pregnancy to continue. Mifepristone is a derivative of norethindrone with antiprogestin action. It binds to progesterone receptors in the endometrium and decidua, resulting in necrosis and detachment of POCs.', 'role': 'assistant'}]