There can be considerable biological variation in sperm production, so that if output has always been depressed, it does not take much for there to be no sperm at all on one or even two samples. Such variability is known as Cryptozoospermia - the 'Crypto' prefix literally means 'hidden'
Sometimes there is a temporary interruption in sperm production or ‘spermatogenesis ' caused by reversible or transient factors. Top of this list are anabolic steroids and some supplements, taken to enhance performance and muscle bulk.
Viral and other illnesses, particularly when associated with fever, may also cause 'recoverable' Azoospermia.
But when there really are no sperm to be found, and when there is nothing to suggest obstruction or some failure of the ejaculatory mechanism, then we expect some failure of the process of 'spermatogenesis' in the testicle itself. We will always look for genetic causes, by doing a blood test or Karyotype which checks for major chromosome abnormalities which may explain the situation. Further blood tests for hormone levels are also necessary, as we can sometimes use medical treatments to attempt to provoke sperm production.
When despite the relevant diagnostic tests and appropriate initial treatment we are still faced with Azoospermia, we would usually propose a surgical procedure called Micro Testicular Sperm Extraction or MTESE. This is a day case operation under general anaesthetic which has two purposes. First to diagnose the cause of the problem, which is possible in all cases, and second to attempt to retrieve sperm, possible in approximately 50 percent of men.
The operation is made possible by the use of a microscope which allows the surgeon to identify tiny areas within each testicle where islands of sperm production still exist, despite a background of failed spermatogenesis. This is why 'simple' testicular biopsies or small random samples may result in the conclusion that nothing can be done, because the random 'biopsy' just happened to come from a site of failed spermatogenesis.
Sometimes we might suggest an alternative diagnostic procedure called 'Testicular Mapping' . This is not a sperm retrieval operation as it is merely diagnostic, but it may lead to a more predictable MTESE in the future.
When we expect that the outcome of an MTESE is likely to be positive, either because of a finding of Cryptozoospermia or because of a previous positive Mapping Procedure, we might propose that the retrieval operation (MTESE) could be synchronised with the IVF process. This is clearly a matter for very careful evaluation, for not to find sperm on the day of the egg retrieval is a devastating outcome for all involved.