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: Social & Preventive Medicine
A case of vasectomy is said to have failed as the vasectomised person's wife gives bih to a child ten months after the operation. Which one of the following is the most probable cause? 
Select and explain. 
A. Failure of the husband to use condom after vasectomy, B. Surgical failure, C. Recannalisation, D. Wife had extramarital contact
B: Surgical failure
Answer: B: Surgical failure 
Explanation: Ans. is 'b' i.e., Surgical failure o It is the case of surgical failure as pregnancy occured immediately after surgery (delivery occured 10 months after surgery) o Recanalization occurs after sometime of successful surgery. Women become pregnant 16 months to 3 years after surgery that means delivery will occur 9 months later to this period.