How does vasectomy work? Fact vs Fiction
The first step in learning about vasectomy is to understand how your stuff really works.
Most people think they understand their body and human reproduction. The reality is many of us have very little understanding of how our stuff works!
Once you have a basic understanding of male reproductive anatomy then you can more easily understand how vasectomy prevents pregnancy.
You will also have a better understanding of why many of the common myths about vasectomy are incorrect.
Each section below expands to explain key areas of the male reproductive system.
Male Reproductive Anatomy: Vasectomy Explained
Scrotum: Protecting the family jewels
The scrotum is composed of skin, very thin layers of muscular tissue, and a very tough layer of connective tissue called fascia.
Each testicle is supported by it's own connective tissue sac and this connective tissue is called fascia.
The scrotum is actually two smaller internal sacs within a single external sac of skin.
The smaller internal fascial sacs each contain, support, and protect a testicle. The thin muscular layer surrounds the fascial sacs and testicles and the muscular layer contracts or relaxes to raise or lower the scrotum to help regulate the internal temperature. The scrotum holds the testicles outside the body because human sperm require a temperature lower than body temperature for proper sperm production and development.
Testicular support is exclusively provided by the fascial sacs that surround each testicle and, to a lesser extent, the skin and muscle of the scrotum. The vas deferens (the tubes divided during a vasectomy) do not provide testicular support. When you have a vasectomy you will not experience a drop in the testicles or an elongation of the scrotum because the main support structures of the testicles are not involved in a vasectomy procedure.
Vasectomy Myth: After vasectomy your testicles will drop.
Vasectomy Fact: Vasectomy will not cause your testicles to drop because the vas deferentia are not the main support for the testicles.
Blood vessels and nerves: Sustaining sperm and hormone production
The blood vessels provide blood supply to the scrotal structures and provide nourishment to the sperm and hormone making cells in the epididymis and testicles. The blood vessels also absorb hormones produced by the testicles and transport these hormones to the rest of the body. The nerves are adjacent to the blood vessels and we can simply say the nerves provide the necessary feedback to let you know when your jewels are in harms way.
A vasectomy has minimal impact upon the blood vessels and the nerves of the scrotum. The scrotal nerves are mostly part of the visceral nervous system. The visceral nervous system is thought of as a primitive network of nerves that work very well to transmit sensation but are not smart enough to always help the brain localize where pain is coming from.
Although most of us know scrotal nerves transmit pain extremely well, these nerves are much easier to anesthetize with local anesthetic when compared to other types of nerves and this is why vasectomy can easily be performed under local anesthesia.
Vasectomy Myth: After vasectomy sex will be less pleasurable.
Vasectomy Fact: Vasectomy does not involve the nerves and does not change the blood supply to the testicles. Many studies suggest improvement in sexual satisfaction after vasectomy for both men and women due to the removal of the fear of pregnancy.
Testicles: Making the hormone that makes you a man
The testicles are responsible for producing testosterone. Testosterone is absorbed by the blood vessels and transported throughout the body by the circulatory system. The hormones produced by the testicles also help sperm development in the epididymis. Vasectomy does not change the production of hormones.
Vasectomy Myth: After vasectomy your hormones will change and you will be less of a man.
Vasectomy Fact: Vasectomy does not decrease or change testosterone production. You will still be a man and your voice will be unchanged!
Epididymis: Sperm factory in constant production
The epididymis is the collection of small tubes on the outside of the testicles. The epididymis is where sperm are created. As sperm are made in the epididymis they move into the vas deferentia and up into the body. Hormones produced in the nearby testicles assist with sperm creation and maturation.
VasectomyMyth: Vasectomy makes you stop making sperm.
Vasectomy Fact: Vasectomy does not stop sperm production in the epididymis; however, as the length of time increases after vasectomy the epididymis may begin to produce less sperm as a direct result of a vasectomy procedure. This is often unnoticeable and is only a problem if you are seeking a vasectomy reversal to restore fertility.
Vas deferens: Sperm highway
The vas deferens is the tube which connects the epididymis to the seminal vesicles inside of the body. There is usually one vas deferens tube that connects to each epididymis. Most men have two vas deferentia but some men can be born without a vas deferens on one or both sides.
As sperm are gradually produced they slowly travel up the vas deferentia and are stored inside the body in the seminal vesicles.
Vasectomy interrupts the transport of sperm. The vas deferens can best be thought of as the ‘transport highway for sperm’. Interruption of the vas deferens stops the transportation of sperm but does not alter or otherwise change the testicles’ production of hormones or the continued creation of sperm.
Vasectomy Myth: After vasectomy everything changes.
Vasectomy Fact: Vasectomy only blocks the tubes that allow sperm to travel up from the testicles.
Using a comparable analogy: if a plumber turns the water off to your house then your house will not have any water but your electricity, heating and air, and television will continue to work.
Vasectomy is a procedure which only blocks transport of sperm up the vas deferens. If you were to have a rare vasectomy complication you could experience change but most men will not experience any noticeable change after vasectomy.
Dilated Ductus Deferens and Seminal vesicles: Sperm staging area
Each vas deferens becomes larger in the area underneath the bladder and just before the tubes enter into the prostate. This larger area is called the dilated ductus deferens and this is where sperm 'hang out' until they are released with ejaculation.
The seminal vesicles are important because these sacs produce fluid that nourishes sperm and helps sperm transport during ejaculation.
Each vas deferens and seminal vesicle joins with the prostate. Prostatic fluid also helps transport sperm during ejaculation. The fluid released by the prostate increases the motility (movement) of the sperm.
A vasectomy interrupts the transport of sperm to the seminal vesicle storage area. Even with a successful vasectomy live sperm will remain in the enlarged dilated portions on the vas deferens until they are released.
Failure to use a back up method during the first three months after vasectomy is the most common reason for pregnancy.
Vasectomy Myth: Vasectomy is instantly effective.
Vasectomy Fact: Vasectomy instantly causes interruption of sperm transport but after vasectomy you have live sperm stored in the seminal vesicles. Pregnancy is possible until these sperm are cleared.
Prostate: Providing the fluid for sperm transport
The seminal vesicles and the prostate secret over 95% of the fluid released during ejaculation. The actual volume of sperm in the ejaculate is very small (less than 5% of the total volume of the ejaculate).
Describing a large cup of coffee provides a great analogy for how much fluid the prostate and seminal vesicles provide during ejaculation. The coffee in the cup is comparable to the fluid released during ejaculation. The sperm in the ejaculate add as much volume as would several packets of sugar when added to a large cup of coffee, which is essentially an unnoticeable amount of volume.
After vasectomy some men may notice a slight change in the color of their ejaculate because of the absence of sperm but the volume of fluid is only minimally decreased and often not noticeable.
Vasectomy Myth: After vasectomy the amount of fluid you ejaculate during intercourse decreases. Vasectomy causes prostate problems.
Vasectomy Fact: Vasectomy does not decrease the amount of fluid during ejaculation. Vasectomy has no involvement with the prostate.
During a vasectomy procedure an opening is simultaneously made in the skin, thin muscle layer, and fascial layer of the scrotum and each vas deferens is exposed, divided, and permanently closed.
Vasectomy is intended to achieve one result: highly reliable, safe, permanent birth control with a very low risk of complications and side-effects.
After the vasectomy the seminal vesicles must be emptied of remaining sperm and only then vasectomy can be reliably counted on for permanent and highly effective birth control.