Absolute azoospermia is a condition where men have no motile sperm. It is not uncommon for men to have low sperm motility. Often this is situation can be resolved with positive lifestyle changes. However, absolute azoospermia is a more complicated situation.
It is estimated that 1 in 5,000 men do not product motile sperm in their ejaculate[1. “Emiliani S, et.al. (2000). Increased sperm motility after in-vitro culture of testicular biopsies from obstructive azoospermic patients results in better postthaw recovery rate. Human Reproduction. Volume 15, (pp.2371-4).”}.
This means that the sperm are unable to swim forward and therefore are not capable of fertilising the egg[2. “Beauchamp P. et al. (1984). Human sperm velocity and post insemination cervical mucus test in the evaluation of the infertile couple. Archives of Andrology. Volume 13, Issue 2-3, (pp. 107-12.”].
What Causes Absolute Azoospermia?
The absence of motile sperm in ejaculate is generally attributed to two main causes: necrozoospermia or ultrastructural defects in sperm morphology.
Necrozoospermia is a condition where all the sperm in the ejaculate are dead. This is a very rare condition and reporting in 0.2-0.5% of infertile males[3. “Ahmadi A, and Ng S. (1999). Developmental capacity of damaged spermatozoa. Human Reproduction, Volume 14, (pp. 2279-85).”]. The cause of necrozoospermia can be variable and in some causes it is reversible. Some of the common causes include:
- Antisperm antibodies
- Specific metabolic disorders affecting ATP production
- Exposure to environmental pollutants
- Delayed epididymal transport
- Extended periods of anejaculation
- Genital infections
- Oxidative stress
A correct diagnosis of the cause of necrozoospermia is needed to ensure appropriate treatment.
*It is also important to note that some diagnostic tests, such as Testicular Sperm Aspiration (TESA, may retrieve immotile sperm. This is because the cells are immature or still attached to sertoli cells (‘nurse’ cells). It does not necessarily mean a diagnosis of persistent absolute azoospermia.
Ultrastructural Sperm Defects
In some cases men are unable to produce motile sperm due to abnormal structural morphology. This includes the condition known as immotile-cilia syndrome whereby the sperm count, general morphology and volume is normal, yet the motility is absent.
To determine if ultrastructural defects are the cause of absolute azoospermia an electron microscopy analysis of a sperm sample is necessary.
Diagnosing Absolute Azoospermia
A thorough examination is required to help determine the cause of azoospermia. This includes a review of medical history, medications, past surgery, family history, as well as a physical examination.
Blood tests are taken to investigate testosterone and follicle stimulating hormone (FSH) levels.
Two semen samples are also required. The samples should be produced following a abstinence period of three days. Each sample will undergo a standard analysis.
If no sperm is identified in the first sample a further analysis may be conducted. In this situation the sample is typically spun in a centrifuge to concentrate the sperm for a more detailed investigation.
If it is not possible to identify a cause or treatment for absolute azoosperma the next stage is to isolate sperm that may be used for intracytoplasmic sperm injection (ICSI).
What is ICIS?
Intracytoplasmic sperm injection (ICSI) was developed in 1992 and is now a commonly used assisted reproductive treatment option[3. “Palermo G, et. al. (1992). Pregnancies after intracytoplasmic injection of a single spermatozoon into an oocyte. Lancet, Volume 340, (pp.17-18).”]. This technique involves using a micromanipulator to inject sperm directly into the egg as part of an in vitro fertilisation process. This technology can enable men with severe male factor infertility to still father a child.
However, cases of absolute azoospermia have a very low fertilisation rate using ICSI, especially if the spermatozoa have been selected from the ejaculate[4. “Nagy Z, et.al. (1995). The result of intracytoplasmic sperm injection is not related to any of the three basic sperm parameters. Human Reproduction, Volume 10, (pp. 1123-9).”].
Can Immotile Sperm Still Be Viable?
There are several tests which can be conducted to determine if immotile sperm is viable. One technique is the mechanical touch method. In this procedure the sperm is nudged with an ICSI pipette. If the tail responds with movement and returns to the original position it is consisted viable.
Another method to determine potentially viable sperm is the hypo-osmotic swelling (HOS) test[5. “Casper, R. et. al. 1996). The hypo-osmotic swelling test for selection of viable sperm for intracytoplasmic sperm injection in men with complete asthenozoospermia. Fertility Sterility, Volume 65, (pp. 972-976).”].
During this test sperm are added to a solution which permeates the membranes of viable sperm only. It causes the spermatozoa to ‘swell’ and the tail to curl. This test can be used to help assist in diagnosing and managing male infertility.
Other techniques used include assessment using birefringence-polarization microscopy, pentoxifylline exposure, and non-contact 1.48 mm diode laser to induce sperm tail curling.
No single technique is considered better than another. Some clinics may recommend multiple assessments to determine sperm viability.
If all sperm in ejaculate are dead a TESA procedure may be preformed to help mature sperm outside the testis and determine viability. If this procedure is to occur in conjunction with ICSI it is recommended to retrieve the sperm via TESA on the day prior to egg harvesting. This is because there have been situations where sperm salvaged from TESA and incubated in cultural medium overnight has shown signs of motility.
Fathering Children With Absolute Azoospermia
Men diagnosed with absolute azoospermia will struggle to father children. However, it is important that a thorough examination and sufficient testing is preformed.
Treating correctable causes and/or utilising advanced reproductive interventions may increase the availability of viable sperm. This can elevate conception potential.
Conception rates are shown to vary significantly depending on the origin of the sperm and the techniques used for immotile sperm isolation. Fertilisation rates have been shown to vary from 3% to 76.4%[1. “Liu J, et al. (1997). High fertilization rate obtained after intracytoplasmic sperm injection with 100% nonmotile spermatozoa selected by using a simple modified hypo-osmotic swelling test. Fertility and Sterility. Volume 68, (pp. 373-5).”], [1. “Ron-El R, et.al. (1998). Repetitive ejaculation before intracytoplasmic sperm injection in patients with absolute immotile spermatozoa. Human Reproduction. Volume 13, (pp. 630-3).”]. While pregnancy rates have been shown to vary between 0% and 38.3%[1. “Vandervorst M, et. al. (1997). Patients with absolutely immotile spermatozoa and intracytoplasmic sperm injection. Human Reproduction. Volume 12, (pp. 2429-33).”], [1. “Kovacic B, et.al. (2006). Clinical use of pentoxifylline for activation of immotile testicular sperm before ICSI in patients with azoospermia. Journal of Andrology. Volume 27, (pp. 45-52).”].
Absolute azoospermia is rare. In some cases the condition is temporary. It is essential that a thorough diagnostic evaluation is preformed and all therapeutic interventions are investigated.
In some cases it is still possible for men with absolute azoospermia to conceive a baby. However, this typically involves assisted reproductive technologies, such as ICSI. For further information about absolute azoospermia diagnosis and possible treatment options it is recommended to consult a fertility clinic.