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Cause of Azoospermia


Nearly half of the causes for infertility is associated with male factor. In majority of the circumstances male factor is a result of sperm defect such as defective sperm production, sperm dysfunction and/or impaired sperm transport. Not uncommon is total absence of sperm in the semen among 1% of males and this is called azoospermia.

It can be a result of non-obstructive azoospermia/testicular failure (53%), obstructive azoospermia/genital tract obstruction (31%) or other causes (15%).

Testicular failure can be either primary that is the causing arising from testes directly or secondary which is testicular dynsfunction due to other factors.


In practically all circumstances this diagnosis is made after two semen analysis are performed where is an absence of sperm. Optimal time for the collection of the second sample would be three months as this is the time taken for the spermatogenesis process and transport of the sperm. Therefore it must be remembered that production of semen alone does not exclude male infertility and semen analysis is essential.


Causes of non-obstructive azoospermia include underscended testis, testicular trauma, torsion, inflammation/swelling (due to virus e.g. mumps), iatrogenic (e.g radiotherapy or chemotherapy) and genetic abnormality. The cause cannot be determined in nearly 50% of cases.

The causes of obstructive azoospermia post-infective epididymitis due to sexually transmitted disease, congenital absence of vas deferens and certain rare syndromes.


Clinical assessment would include past medical and surgical history particularly pertaining to the genitourinary system, lifestyle factors and any medication taken. Developmental and pubertal history should also be obtained.

Physical examination would include presence of secondary sexual characteristics with importance given to genital examination. The scrotum is examined to check for the presence of both testis and vas deferens, testis size and consistency and varicocele if any.

Certain blood investigations such as sexual hormonal study would be helpful especially in non-obstructive azoospermia. Occasionally genetic studies may be done.


In most circumstances surgical retrieval of sperm would be required followed by Assisted Reproductive Techology (ISCI). It can be either attempted by a needle aspirate or open surgery at the scrotum. Obviously obstructive azoospermia have the best outcome.

Medical treatment option exists for a small subset of patients where deficiency of gonadotrophin hormones has resulted in testicular function.


  1. Medical & Surgical Management of Male Infertility. Editors; Botros RMB Rizk, Nabil Aziz, Ashok Agarwal, Edmund Sabanegh. Jaypee Publications 2014.
  2. Textbook of In Vitro Fertilization & Assisted Reproduction. The Bourn Hall Guide to Clinical & Laboratory Practice. Editor: Peter R Brinsden
  3. Textbook of Assisted Reproductive Techniques. Clinical Perspectives. Editor: David Gardner, Ariel Weissman, Colin Howles, Zeev Shoham.