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
[{'content': 'Which of the following method is the best predictor for ovulation in a female infertility patient during a menstrual cycle \nSelect and explain. \nA. Basal body temperature, B. Hormonal Study, C. Endometrial biopsy, D. Fern study', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In the anovulatory cycle, plasma progesterone reaches a peak of 15ng/ml at mid-luteal phase (22-23days).\nBasal body temperature (BBT) falls at the time of ovulation by about 1/2degree. During the progestational half of cycle, the temperature is slightly raised above the preovulatory level. But it is now obsolete because:\n\nTedious daily recording\nNot very accurate\nBetter modalities are available\n\n\nIn endometrial biopsy endometrium from the uterus is curetted preferably 1 or 2days prior to the onset of menstruation. Histological examination done for secreatory changes. Now a days endometrial biopsy is omitted as a routine investigation of infertility. Only used in suspected tubercular endometritis\nFern test: cervical mucus is examined under a low power microscope. During estrogenic phase, it shows a charecteristic fern patten which disappears after ovulation', 'role': 'assistant'}]