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 helps to prevent premature LH surge during oocyte retrieval for in vitro fertilization \nSelect and explain. \nA. HCG, B. Oestrogen, C. Progesterone, D. Leuprolide', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Leuprolide (GnRH agonist) prevents the possibility of spontaneous LH surge and ovulation prior to egg retrieval.', 'role': 'assistant'}]