A failed vasectomy is a sterilization procedure for a man that fails, allowing the man to continue producing semen in his ejaculate, as he did before undergoing the vasectomy procedure. If the man has unprotected sex with a fertile woman, a pregnancy can result. Failure of vasectomies is extremely rare, under .2% in most regions, but it can and does happen.
The vasectomy is regarded as a permanent sterilization procedure. In a vasectomy, the doctor cuts the vas deferens, ensuring that semen produced in the testes cannot be ejaculated. It takes around four to six months after the surgery for all sperm to be completely cleared and a lab analysis is usually done to confirm that the vasectomy has worked and there are no sperm in the ejaculate.
People sometimes mistakenly believe that a vasectomy failed because they had intercourse too soon after the surgery, when the man still had active sperm. This is sometimes referred to as a short-term failed vasectomy, referencing the fact that in a few months, the sterilization should be effective. Sometimes, even after six months, the man is still producing sperm in his ejaculate, a consequence of an improperly performed procedure.
In other cases, a phenomenon known as recanalization occurs. In recanalization, the body comes up with a way to work around a severed connection or blockage. In this case, the body remaps the tissues in the male reproductive tract to allow sperm to be ejaculated. This can happen at any time, and doctors may recommend periodically testing the ejaculate to check for signs of sperm that indicate the man's vasectomy has failed.
Failed vasectomy is a rare problem, but it does affect some of the population. It's important for patients to comply with instructions from the surgeon to ensure that they do not have unprotected intercourse too soon after vasectomy. Once a sperm-free test result has been obtained, periodic tests are recommended to confirm that the vasectomy is still working.
When patients experience a failed vasectomy, there are a number of options available to them. The man may want to consider a repeat procedure if he wants to remain sterile. His partner can discuss options for management or termination of the pregnancy with a health care provider. Women with presumably sterile partners should seek medical attention if they experience irregularities in their menstrual cycles. A cessation of periods may mean a pregnancy as a result of a failed vasectomy, or it could be a sign of an underlying health condition that needs treatment.