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
The most common side effect of IUD inseion is: 
Select and explain. 
A. Bleeding, B. Pain, C. Pelvic infection, D. Ectopic pregnancy
A: Bleeding
Answer: A: Bleeding 
Explanation: 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