This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Placenta Previa, Subject name: Gynaecology & Obstetrics
Blastocyst implantation close to internal os causes- 
Select and explain. 
A. Placenta previa, B. Placenta Percreta, C. Placenta increta, D. Abruptio
A: Placenta previa
Answer: A: Placenta previa 
Explanation: Ans. is 'a' i.e., Placenta Previa Placenta Previao When the placenta is implanted partially or completely over the lower uterine segtnent, over and adjacent to the internal os, it is called placenta previa.