This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Follow up of Low-risk GTN is done for \nSelect and explain. \nA. 3 months, B. 6 months, C. 12 months, D. 24 months', 'role': 'user'}, {'content': "Answer: C \nExplanation: For a molar pregnancy, post-evacuation surveillance is done at least for 6 months once b-hCG level becomes normalLow-risk GTNWeekly measurement of hCG levels until they are normal for 3 consecutive weeksMonthly measurement of hCG values until levels are normal for 12 consecutive monthsHigh-Risk Metastatic GTNWeekly determination of hCG levels until they are normal for 3 consecutive weeksMonthly determination of hCG levels until they are normal for 24 consecutive monthsThese patients require prolonged follow-up because they are at increased risk of late recurrenceReference: William's Obstetrics; 25th edition, chapter 20; Gestational trophoblastic diseases", 'role': 'assistant'}]