This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Contraception, Subject name: Gynaecology & Obstetrics
Mirena should be changed after how many years : 
Select and explain. 
A. 2 years, B. 4 years, C. 5 years, D. 10 years
C: 5 years
Answer: C: 5 years 
Explanation: Mirena: Contains 52 mg of levonorgestrol Releases hormone in very low doses Acts for a period of 5years Has low pregnancy rate of 0-3 per 100 women years Ref: Shaw Gynecology 17 e pg 258.