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': 'After evacuation of a hydatidiform mole the risk for choriocarcinoma is considered when: \nSelect and explain. \nA. Beta-hCG value plateaus for 2 weeks, B. Beta-hCG value plateaus for 3 weeks, C. Beta-hCG value plateaus for 4 weeks, D. Beta-hCG value plateaus for 6 weeks', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Following evacuation of the uterus, weekly serum Beta -hCG levels should be monitored until normalized for 3 weeks, followed by monthly testing for 6-12 months depending on assessment of pretreatment risk factors. If the Beta -hCG value plateaus for 3 weeks or rises for 2 weeks, invasive gestational trophoblastic disease, including either invasive mole or choriocarcinoma, should be suspected. Effective contraception during the surveillance phase is impoant in order not to complicate interpretation of the Beta-hCG. Ref: Reynolds R. Loar P.V. (2010), Chapter 39, Gynecology ; G.M. Dohey (Ed), CURRENT Diagnosis & Treatment: Surgery, 13th Edition', 'role': 'assistant'}]