This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Methods - Combined Oestrogen-Progestogen Methods, Subject name: Gynaecology & Obstetrics
[{'content': 'Which of the following is not a mechanism of action of OCPs- \nSelect and explain. \nA. Inhibition of ovulation, B. Out of phase endometrium, C. Alteration of cervical mucus, D. None of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., None of the above o All are true. o Mechanism of action of oral contraceptive pills: i) Inhibition of ovulation :Both estrogen and progesterone act on HPO axis. The release of GnRH from the hypothalamus is prevented through a negative feedback mechanism. ii) Producing static endometrial hypoplasia: There is stromal edema, decidual reaction, and regression of the glands making endometrium non-receptive to the embryo. iii) Alteration of the character of the cervical mucus (thick, viscid and scanty) so as to prevent sperm penetration. iv) Interferes with tubal motility and alters tubal transport.", 'role': 'assistant'}]