This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abortion, Subject name: Gynaecology & Obstetrics
[{'content': "Nitabuch's membrane is absent in: \nSelect and explain. \nA. Placenta accrete, B. Vasa previa, C. Abruption placenta, D. Placenta previa", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Placenta accretaRef: Williams obstetrics 23rded, Ch 35.* The nitabuch layer is a zone of fibrinoid degeneration in which invading trophoblasts meet the decidua. If the decidua is defective, as in placenta accreta, the Nitabuch layer is usually absent.Also Know* Placenta accreta indicates that villi are attached to the myometrium.* Placenta increta, villi actually invade the myometrium.* Placenta percreta defines villi that penetrate through the myometrium and to or through the serosa.', 'role': 'assistant'}]