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The Facts About the Vas Deferens

Find out how the vas deferens affects your sexual health.

A dictionary page is showing the term vas deferens.

The vas deferens—also known as the sperm duct—is part of the male reproductive system.


Every male has two vas deferens, one in each testicle, that run from the epididymis to the pelvic cavity behind the bladder. The vasa deferentia (plural) then connect to the urethra through an ejaculatory duct.


The vasa deferentia are found in the male scrotum, which holds a man's testicles. They connect to each testicle's epididymis and enter into the body in the pelvic region, along the spermatic cord vessels, until they join with ejaculatory ducts, which connect them to your urethra. Each vas deferens originates off the tail of the epididymis and is about 12 inches (30 centimeters) in length.

It is made up of both fibrous tissue and muscle tissue.


Sperm production occurs in the testicle and the sperm are stored in the epididymis until they're mature enough to fertilize a female egg. During a male orgasm, muscle contractions move the sperm to the vas deferens, which is responsible for sending them to the urethra. The sperm then mix with secretions from the body to compose semen and are ejaculated out of the penis.

The vasa deferentia are cut off from transporting sperm cells in a procedure called a vasectomy, a form of male birth control.

Prostate and the vas deferens

Semen is made up of secretions and additives that join sperm sent from the vas deferens. Some of those secretions originate in the prostate gland. When prostate complications such as cancer arise, the vasa deferentia can be affected. If the prostate is removed, for example, some of the secretions that combine with sperm cells to create semen cannot be produced, making infertility an unavoidable and permanent problem. Other treatments, such as radiation, may also affect the production of semen and the creation of sperm cells in the testis.

How to care for your vas deferens

Taking care of your overall health is important for your testicle health and, therefore, prevention of any issues with the vas deferens. In general, follow these rules to ensure your physical well-being and that of the vas deferens:

  • Eat a balanced diet
  • Maintain a healthy weight
  • Exercise
  • Stay hydrated
  • Wear protective equipment if you play sports
  • Avoid alcohol and tobacco products
  • Check your testicles regularly. If anything looks or feels different than normal, including pain or swelling, see a healthcare specialist.

Sex and the vas deferens

Banking sperm and sperm extraction are options to consider prior to undergoing any form of prostate treatment that could affect the function of the vasa deferentia. This is especially true for anyone about to undergo chemotherapy. These options are usually recommended before a vasectomy, too. Vasectomy reversals can be successful, but having sperm banked is a good fallback plan.

Preparing your vasa deferentia for a vasectomy

During a vasectomy, the vasa deferentia are cut and sealed to prevent sperm from reaching the semen.

If a vasectomy is performed, your recovery time should be short, and the pain usually can be kept to a minimum with ice and pain relievers, such as acetaminophen or ibuprofen. Blood may temporarily appear in the ejaculate, but that should resolve itself in a few weeks. A man can resume his sex life after the vasa deferentia heal from the vasectomy, usually after a couple of weeks.

Sexual dysfunction and the vas deferens

One or possibly both vas deferens may be blocked from birth or by a complication called ejaculatory duct obstruction. Fertility complications may result if both ducts are blocked. Azoospermia (the absence of sperm in the semen) or aspermia (the absence of semen with ejaculation) may also stem from blocked vasa deferentia. A surgery called transurethral resection may reopen the ducts and allow the flow of sperm.

In some instances, a vas deferens may be damaged during surgery for BPH, which could cause retrograde ejaculation, in which ejaculate goes into the bladder rather than emerging through the penis.

How to keep the vas deferens healthy

Keeping the vas deferens healthy is important to a man's reproductive system. There are a number of tests or exams doctors can perform to ensure the vas deferens is functioning properly:

  • Physical exam of the penis, testicles and scrotum
  • Ultrasound
  • Magnetic resonance imaging (MRI)
  • Urine tests
  • Blood tests
  • Semen analysis
  • Biopsy

Practice safer sex to avoid sexually transmitted diseases (STDs) or infections (STIs). Regular physical exams should be performed by a doctor. Depending on the results of the exams, an ultrasound, an MRI, lab tests, semen analysis or a biopsy may be performed.

Antibiotics are usually prescribed to treat any infections. Surgery is rare but may be required in the case of blockages, masses or cysts.


What is the function of a vas deferens?

A man usually has two vas deferens, one in each testicle. The job of a vas deferens, also sometimes called a sperm duct, is to move sperm from the epididymis to the urethra so it can be ejaculated with semen.

What happens if the vas deferens is blocked?

A blocked vas deferens causes obstructive azoospermia, meaning a man makes healthy, normal sperm, but that sperm cannot travel out of the epididymis to enter the ejaculate. A vas deferens can be blocked by scarring from an STD or congenital cysts, which are present from birth.

A vasectomy is a surgical procedure that severs the vas deferens so sperm cannot enter the ejaculate. Men choose to get a vasectomy for birth control purposes.

How long is the vas deferens?

The vas deferens can be 30 centimeters (nearly 12 inches) long. Some parts are curled, while others are straight.