What Are the Causes of Vasectomy Failure?

A vasectomy has about the same level of effectiveness as the birth control pill; in effect, it usually only has about a 1 in 100 chance of failing. The most common time frame for a vasectomy to fail is directly after the procedure is completed. This is why physicians advise their patients to use another form of contraception until a follow-up examination--including a semen sample--determines that a vasectomy has been successful.

Time Frame

Following the completion of a vasectomy procedure, sperm can remain active in the male reproductive system for several weeks. Therefore, unprotected sex during this time can result in a pregnancy. Doctors usually take a semen sample 6 to 8 weeks following a vasectomy in order to check sperm count and the success of the procedure.

Misconceptions

Many people believe that a vasectomy prevents a man from ejaculating altogether; this is untrue. A vasectomy prevents the release of sperm when a man ejaculates, but doesn't prevent or discontinue ejaculation altogether.

Considerations

Very rarely, a vasectomy is unsuccessful. This is sometimes due to a technical error on the part of the surgeon; however, most often it's caused by the spontaneous reconnection of the severed ends of the vasa deferentia, which are cut to prevent sperm from being released during ejaculation. This spontaneous reconnecting is known as recanalization.

Prevention/Solution

To reduce the chances of recanalization, some doctors prefer to leave a gap between the two cut ends of the vasa deferentia. Although this is not common procedure, it's done by some doctors who believe it can reduce the chances of a vasectomy's failure.

Statistics

Approximately 0.5 percent to 1 percent of all vasectomies fail. This variation is due largely to how the procedure is performed and whether or not the patient returns for follow-up semen testing.