By Cristina Mestre Ferrer BSc, MSc (embryologist).
Last Update: 04/01/2014

There are many cases of couples trying unsuccessfully to conceive during a whole year. In 30% of cases, it is due to male fertility problems, while 20% are due to both male and female causes.

A seminogram is the most common sort of test to check fertility in men. To perform this test a seminal sample should be obtained after ejaculation and then it is evaluated at the laboratory in order to check the number and the status of the sperm.

Definition and diagnosis of azoospermia

Azoospermia, commonly referred to as “no sperm count”, is described as the absence of measurable sperm in a man’s ejaculate (semen). It is estimated that, among all male infertility problems, azoospermia is present in between 3 and 10 per cent of cases.

Azoospermia is a medical condition with no noticeable symptoms. This is the reason why, for its diagnosis, it is necessary to determine the FSH hormone levels, which is produced by the brain and is the responsible for spermatogenesis (production of spermatozoa) in the male testes. If they are too high it means a decreased level or the absence of stem cells in sperm. Performing a testosterone concentration analysis is also advisable.

Seminiferous tubule of azoospermic man

There are two types of azoospermia: on the one hand, secreting or non-obstructive azoospermia, in which the testes are not capable of producing sperm; on the other, obstructive azoospermia, in which sperm can be found but they cannot be expelled with the man’s ejaculate because of an obstruction in the vasa deferentia (a.k.a. ductus deferentes).

Carrying out a testicular biopsy is necessary in order to determine the type of azoospermia. It consists of taking a tissue sample from the each testicle in order to check if it produces sperm (obstructive azoospermia) or not (secreting azoospermia).

Secreting or non-obstructive azoospermia

Secreting or non-obstructive azoospermia is the most severe, frequent type of azoospermia, being present in 70% of cases. It can be congenital (condition existing at birth) or acquired (due to an illness or treatment with toxic medicines). These are the most common causes:

  • Abnormalities of testicular descent.
  • Exposure to toxic substances: drugs, radiotherapy, and chemotherapy.
  • Genetic disorders.
  • Hormonal alterations.
  • Testicular diseases: mumps, traumatisms, inflammations, and severe varicocele.

Sperm retrieval when suffering from non-obstructive azoospermia is complicated, since no sperm is generated. Nonetheless, pregnancy is possible. In some cases of male infertility, minor concentrations of sperm have been found in the testes. Therefore, multiple and small testicular biopsies are performed in order to find sperm. If any sperm is found, it will be frozen and used later in an ICSI treatment.

Image of secreting or non-obstructive azoospermia

Obstructive azoospermia

Obstructive azoospermia is due to a problem in the sperm ducts which transport the sperm from the testicles to the urethra, in which the ejaculate occurs. The most common causes of this type of azoospermia are:

  • Absence of vasa deferentia –either because of congenital reasons or after a surgical intervention.
  • Inflammations or traumatisms in the testicle, the epididymis, the vas deferens, or the prostate.

However, obtaining sperm is easier with this medical condition. Some particular cases suffering from this type of azoospermia can be treated and reversed. The obstruction can be removed or the separated ducts can be reunited by means of different microsurgery techniques, which will allow sperm to be found in semen.

Where this is not possible, sperm would be collected from the testicles with a testicular biopsy. Usually, a single biopsy is enough, since spermatogenesis occurs in a normal way.

Image of a obstructive azoospermia

Azoospermia and varicocele

The relationship between azoospermia and varicocele is rather common, since 5% of varicocele cases end up developing azoospermia. However, this only occurs among the most severe cases of varicocele.

Varicocele is defined as an abnormal enlargement of the veins found in the human male spermatic cord, determined by an enlargement of the spermatic veins. It affects spermatogenesis directly.

Azoospermia and varicocele

Secreting azoospermia patients who undergo techniques for correcting varicocele usually recover 50% of their testicular tissue. In addition, sperm motility after ejaculation is recovered in 55% of cases.

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Authors and contributors

 Cristina Mestre Ferrer
BSc, MSc
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information
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