Sperm transport obstruction is the second most common cause of male infertility. These blockages of the tubes (the epididymis and vas deferens) carrying sperm away from the testes can prevent proper semen ejaculation. This obstruction may occur at any location from the epididymus through to the ejaculatory ducts located in the prostatic urethra. Approximately 30% of infertile men suffer from this condition.

The causes of sperm transport obstructions can be congenital or may develop over time. In the case of vasectomies, the obstruction is a deliberate form of contraception. The four main causes of sperm transport obstructions are:

 Infections: Infections within the reproductive tract may cause blockages that prevent proper sperm transportation. Sexually transmitted diseases, including especially Chlamydia, mycoplasma, and gonorrhoe, are the most common source of infection. These infections can damage the epididymis, causing scaring and blockage. The epididymis is located adjacent to the testicle and obstructions can prevent sperm from leaving the duct. This may not change ejaculate volume, however, these obstructions will significantly reduce sperm count and cause infertility.

There are a range of different reatment options for men whose fertility has been affectd by infections. Often once an ongoing infection has been diagnosed it can be treated and fertility restored. However if  the sperm transport tract has been damaged, surgery may be required to remove obstructions. The success rate of these procedures is high and usually men regain fertility. In severe cases, removal of sperm for ARTs may be the only option.

Prostrate relate causes: The ejaculatory duct passes through the prostate gland. Any infections of the prostate can result in swelling and obstructions that prevent sperm from being ejaculated. A blockage in this location will also reduce volumes of ejaculate as the fluid is produced by both the prostate and seminal vesicles.

In some cases, infections of the prostate can also directly damage sperm cells. Congenital abnormalities may cause cysts to form on the prostate gland, resulting in compression of the ejaculatory ducts, thus blocking sperm transportation. Surgery to remove cysts or other blockages can help to restore fertility.

Vas deferens absence: The vas deferens is responsible for the transportation of sperm to the ejaculatory ducts from the epididymis. In approximately 1% of men the vas deferens is absent. This congenital condition is often accompanied by a shortened epididymis, which is caused by a genetic mutation to the cystic fibrosis transmembrane regulator (CFTR) gene and is usually coupled by an absence of seminal vesicles. This causes reduced ejaculate volume from approximately 2 ml to around 0.5 ml. Ejaculate is also more acidic in the absence of seminal vesicles.

Unfortunately, there is no surgical way to replicate the vas deferens. Nevertheless, it is possible to retrieve sperm from the ducts within the existing epididymis or testicle. This sperm can be frozen and used for IVF or other assisted reproductive technologies (ARTS). However, as this condition arises from a genetic mutation, it is important to undertake genetic testing of both partners. If CFTR mutations are identified in both partners, the risk of cystic fibrosis is high in their offspring born from ARTs.

Vasectomy: The most common cause of sperm transport obstruction is a vasectomy. This surgical procedure involves removing a section of the vas deferens. The vas deferens is responsible for carrying sperm to the urethra at the bottom of the bladder. This is a long-term, safe contraceptive option, however, many men later choose to have the procedure reversed so that they can father more children.

Although there are no long-term changes to a male’s levels of testosterone following a vasectomy, the sperm producing tubes can be damaged over time. Also, blockages and scaring of the epididymal tubes occurs frequently. In 80% of men that have had a vasectomy, sperm antibodies form, therefore, a vasectomy reversal is less successful the longer time passes.


In many cases, there may be no obvious symptoms associated with sperm transport obstructions, however, If the cause of the blockage is infection, there may be some unusual discharge from the penis, inflammation, and discomfort while urinating or ejaculating. Less than normal ejaculate volume are also a sign of a blockage.



Excluding the absence of a vas deferens, most sperm transport obstructions can be reversed by performing surgery.

In the case of vasectomy reversals, a microsurgical vasovasostomy may be performed. This procedure aims to restore fertility by reconnecting the severed vas deferens.

Other obstructions within the sperm transport ducts may be treated using a vasoepididymostomy, or transurethral resection of the ejaculatory duct (TURED).

A TURED procedure involves opening blockages with a cystoscope passed through the urethra and into the ducts. A vasoepididymostomy is the most common microsurgical method for fixing epididymal obstructions, however, it is also the most difficult and requires a highly experienced and skilled surgeon. This procedure involves the surgical joining of the epididymis and the vas deferens to allow for optimal fluid transport.


Instead of undergoing reconstructive surgery, some men would rather undertake a procedure to remove viable sperm for ARTs. This is also an option for men ineligible for a microsurgical vasovasostomy, vasoepididymostomy, or TURED surgery. There are multiple procedures available for removing sperm.


While under local anaesthetic, your sperm is removed from the epididymis using a fine butterfly needle.


This procedure allows sperm to be retrieved in greater numbers compared with PESA, however, it is more invasive. It involves retrieving sperm directly from individual epididymal tubes with the help of a microscope.


This procedure involves recovering sperm from the testicles using a needle and syringe to puncture the testis and aspirate sperm without the need for a scrotal incision.


  • Semen Analysis: A semen analysis is often the first step in determining if a sperm transport obstruction is present. If sperm are absent from the sample or in very low numbers, it’s a good indication that a blockage may be present.
  • Transrectal ultrasound: High-frequency sound waves are used to create precise images of structures inside your body. This may be used to ensure that there isn’t another reason for your symptoms. Further imaging may be recommended to rule out other causes for the varicocele in some cases such as a tumor compressing the spermatic vein.