Azoospermia is the absence of spermatozoa in the ejaculate, and it is classified as obstructive or non-obstructive. In cases of non-obstructive azoospermia the sperm is recovered surgically.

In obstructive azoospermia, sperm production is normal but no sperm appear in the ejaculate due to an obstruction of the male reproductive tract. The obstructive aetiology includes obstruction of the vas deferens, congenital absence of the vas, or vasectomy. In obstructive azoospermia sperm can be easily obtained surgically using aspiration (FNA) or testicular biopsy (TESE).

In non-obstructive azoospermia there is no production of spermatozoa in the testicles. This complete lack of production or minimal production of sperm (oligoasthenoteratospermia, which is practically as severe as azoospermia) suggests testicular failure. The condition can be idiopathic or be attributed to lack of testicular descent, injury, inflammation, contractible diseases (such as mumps), radiation, chemotherapy or chromosomal abnormalities.

In non-obstructive azoospermia, it is quite rare to retrieve sperm following testicular biopsy (TESE). The chances of retrieving sperm may increase when small areas of spermatogenic activity are detected in the testes, although the number of pregnancies achieved is limited. If there is a high chance of no sperm retrieved, the couple needs to be informed beforehand with regards to their options which can be:

• Use of donor sperm
• Oocyte cryopreservation (vitrification)
• Donation of the oocytes collected, or a combination of these options.