Vasectomies are highly effective in eliminating sperm, with a success rate of 98-99%. However, they do not eliminate all sperm.
Men should continue to use birth control until a semen analysis shows no sperm in the sample. This can take several months.
The numbing medication used during the procedure can sting and cause slight pain when you ejaculate.
Semen Analysis
Men who have had a vasectomy don’t know for sure whether it was successful until they test their semen and see that the results show no sperm present. Without this important follow-up sperm test, many men end up fathering unwanted pregnancies.
To find out if their vasectomy worked, a man should provide a sample of his semen to a urologist for testing. This can be done in a doctor’s office or with a home kit that allows the man to collect his own sample and send it to the laboratory for testing. A sperm count is necessary because a vasectomy only blocks the flow of sperm, but it doesn’t prevent sperm from being produced in the testes. If a test shows that there are still sperm in the semen, then the procedure has not been successful and the man should return to a doctor for a repeat surgery.
According to a study of 214 men who underwent ligation and excision vasectomies, it takes 12 weeks (or about 20 ejaculations) for most men to reach azoospermia, meaning that no sperm is detected in the semen. However, the researchers also noted that the time required for a man to reach azoospermia is much more variable than once thought, and some men reach it in as little as two weeks.
Ejaculation
The testicles (testes) still produce semen after a vasectomy, but the path that sperm takes to the penis is blocked. It is possible to get an erection and ejaculate, but the semen won’t contain sperm. The testosterone level and other male sex traits remain the same, too.
Men who have had a vasectomy can resume having sex soon after the operation, but it’s important to use another form of birth control until a semen analysis shows that there are no functional sperm in the body. This is usually about three months after the surgery.
The sperm produced in the testicles passes down a tube called the epididymis. It’s connected to the vas deferens, which runs from each testicle into the urethra. During sex, the sperm is propelled through the ejaculatory duct by pulsing muscle movements. The semen then exits the body through the penis.
The sperm clearance process can take longer than expected for some people. In one study, it took about 12 weeks for a man to reach “azoospermia,” which means that there were no motile sperm left in the body. The average number of ejaculations needed to reach this stage is about 20. A small percentage of men, however, may never reach azoospermia after a vasectomy. This is because the valve between the bladder and urethra may stay open after some types of vasectomies. This is called retrograde ejaculation and is not harmful or painful.
Sperm Clearance
There is a chance that some men will still have sperm in their semen even after vasectomy. This is why it is very important to continue using birth control until a sperm analysis shows that there are no sperm in the sample. This should happen within a few months after vasectomy. It is important to do several semen analyses to make sure that no sperm are present.
A sperm clearance test is done by taking a small sample of the semen. It is then examined under a microscope to see if there are any sperm present. If sperm are found, it means that the vasectomy has not been successful. The sperm must be eliminated through several ejaculations before it will be safe for a man to have unprotected sexual relations with his partner.
Many doctors recommend annual rechecks of the vasectomy site. This is done to prevent recanalization of the vasa deferentia, which could lead to a failed vasectomy.
A recheck after 3 months will show whether or not a man can be cleared to have unprotected sexual activity. The majority of men will be able to have sex without any problems as long as they follow the proper precautions. Men that cannot be cleared should use a different method of birth control until the sperm count is zero.
Re-canalization
If the sperm count is still high, doctors will perform a procedure called re-canalization. This is where they insert a needle through the epididymis into the vas deferens and reopen the cut ends of the tube.
During this procedure, doctors will look for any signs of sperm and make sure the tube is completely open. The results of this procedure are not always conclusive and it is still important for patients to continue using other methods of birth control until a semen analysis shows zero sperm.
Re-canalization can be a painful process and may require anesthesia. However, it is much faster and more accurate than the original procedure. It also helps to prevent a repeat vasectomy due to an improperly closed canal.
It is possible for the sperm to return after the vasectomy even without an infection, as the incision site can heal on its own or be irritated by sex. Typically, re-canalization occurs in the first couple of weeks post-vasectomy and before the patient is given the all clear by semen analysis.
It is very rare for a man to become pregnant after vasectomy because the procedure closes off the ends of the tubes that carry sperm. Men should be properly counseled about the permanency of the procedure and the availability of highly effective reversible methods of contraception.
