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': 'The most common side effect of IUD inseion is: \nSelect and explain. \nA. Bleeding, B. Pain, C. Pelvic infection, D. Ectopic pregnancy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The most common side effect of IUD inseion is bleeding. Ref:PSM and Biostatistics: Slef Assessment and Review - Park, 17th Edition, Page 341 and 18th Edition, Page 365', 'role': 'assistant'}]