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': 'The earliest morphological evidence of ovulation on endometrial biopsy is: \nSelect and explain. \nA. Pseudostratification, B. Basal vacuolation, C. Decrease in glycogen content, D. Predecidual reaction', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Endometrial biopsy was used in the past to find out whether the female has ovulated or not. Nowadays USG follicular monitoring is being done\nSubnuclear basal vacuolation is characterized by glandular growth and presence of vacuoles due to secretion of glycogen between nuclei and basement membrane. It is due to the effect of progesterone.\nBasal vacuolization is the earliest evidence of ovulation (36-48 hours after ovulation) and persists until the about 21st day of the cycle.\nPseudostratification of nuclei is characteristic of proliferation phase but persists until active progesterone secretion begins. Hence, it is noted until the 18th 19th day of the menstrual cycle.', 'role': 'assistant'}]