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': 'Placental villi invading through the serosa of uterus falls under category of \nSelect and explain. \nA. Placenta pre, B. Placenta accreta, C. Placenta increta, D. Placenta percreta', 'role': 'user'}, {'content': "Answer: D \nExplanation: Variants of the morbidly adherent placenta are classified by the depth of trophoblastic growth.Placenta accreta indicates that villi are attached to the myometrium. With placenta increta, villi actually invade the myometrium, and placenta percreta defines villi that penetrate through the myometrium and to or through the serosa.Reference: Reference: William's Obstetrics; 25th edition; Chapter 41; Obstetric hemorrhage", 'role': 'assistant'}]