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
Unsuccessfulness of DMPA has been primarily because of : 
Select and explain. 
A. Breakthrough bleeding, B. Effect on lactation, C. Delay in return of feility, D. Failure rate
A: Breakthrough bleeding
Answer: A: Breakthrough bleeding 
Explanation: Breakthrough bleeding