What is azoospermia?

by Lefteris Gavriil, last updated 05 Nov 2021,

3 min read

Numerous men worldwide deal with infertility problems for which they have little or inadequate information about. One of the most severe issues associated with male infertility is azoospermia, which is defined as the total absence of spermatozoa in the seminal plasma.

Azoospermia is confirmed by performing a semen analysis examination. According to the World Health Organisation (WHO), a sperm sample should be microscopically examined and if no spermatozoa are observed, a second semen analysis should be carried out approximately 1-2 months after the first analysis in order to confirm this result.

Nowadays, approximately 15% of infertile men are diagnosed with azoospermia. The type of azoospermia can be classified according to the localisation of the problem as Pre-testicular, Testicular or Post-Testicular and the causes can be congenital, acquired or secondary/idiopathic. Azoospermia can also be classified according to the nature of the problem as obstructive azoospermia and non-obstructive azoospermia.

Obstructive azoospermia

In cases of obstructive azoospermia the testes do produce spermatozoa but a physical obstruction between them and the ejaculatory ducts, is present. Congenital azoospermia is a different type of obstructive azoospermia, which is characterised by the complete absence of the vas deferens and its aetiology has been associated with mutations of the cystic fibrosis transmembrane regulator (CFTR) protein. Approximately 40% of azoospermic men suffer from obstructive azoospermia.

Non-obstructive azoospermia

In cases of non-obstructive azoospermia the problem is not associated with a physical blockage, but with an impairment in the process of spermatogenesis. This can be a result of primary testicular failure, secondary testicular failure or incomplete or ambiguous testicular failure. Approximately 60% of azoospermic men suffer from non-obstructive azoospermia.


Different types of azoospermia require different medical therapeutic procedures and therefore it is important to have a detailed diagnosis in order to determine the optimum treatment approach. For this reason, apart from a semen analysis, it is essential to obtain a detailed medical history (e.g. traumas, surgeries, medication), to perform a physical examination (e.g. evaluation of secondary sex characteristics), to have an ultrasonographic evaluation, to perform genetic tests (karyotype, Cystic Fibrosis and Y microdeletions), and to perform hormonal analyses (e.g., FSH, LH and testosterone levels).

It is of utmost importance to obtain a very detailed medical history as for example, previous urethritis or epididymitis (infections of the male reproductive system) can cause obstructive azoospermia, whereas late mumps orchitis can lead to non-obstructive azoospermia. Previous systemic diseases (e.g. diabetes, cirrhosis, chronic renal insufficiency) may also provide useful information as they have been proven to impair fertility-related procedures such as sperm production and transfer.

Valuable information can also be obtained by the volume of the ejaculate, the volume of the testis and the serum hormonal levels (LH, testosterone, and mainly FSH). For instance, azoospermic men with normal ejaculate volume are most likely dealing with a physical blockage of the epididymis or vasa, or impaired spermatogenesis. On the other hand, azoospermic men with normal testicular volume but low ejaculate volume are most likely dealing with obstructive azoospermia, due to a blockage of the ejaculatory ducts. Previous studies have also shown that in non-obstructive azoospermia cases the ejaculated volume, as well as the pH and the fructose levels in semen, are normal. In addition, FSH and LH are well-known key factors of spermatogenesis.

Finally, genetic analysis may also contribute to the diagnosis of azoospermia and can determine if the aetiology is related with pre-testicular, testicular or post-testicular function.
The importance and necessity of accurate diagnosis to differentiate the type of azoospermia has been highlighted, and it is the first and most decisive step in the long pathway of therapeutic implementation. This differentiation is vital given that different cases of azoospermia require different treatment strategies.

Our experience and up-to-date knowledge on this type of infertility, here at Newlife IVF Greece, allows us to be able to guide our patients on the correct pathway that will lead them to a successful treatment cycle. For a free medical consultation appointment during which we can discuss your medical history and future steps, feel free to click on the following link: newlife-ivf.co.uk/consultation

Lefteris Gavriil

Lefteris Gavriil, BSc, MSc

Lefteris is an Embryologist at the Newlife IVF Greece clinic.

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