There is always the possibility that the vasectomy may not work. The recommendations are that you are clear after 20 ejaculations to clear the ducts of sperm before the eight-week sperm check.
Less than that would leave the remote possibility of residual sperm being present in the ducts. Again, it all has to do with probability - chances are that the vascectomy will have worked but the chances of success will increase after the recommended post-op course.
These questions can be discussed with your urologist.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
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