By Zaira Salvador BSc, MSc (embryologist).
Last Update: 12/04/2018

Oligospermia or oligozoospermia is a sperm disorder that causes a low sperm count in the ejaculated semen.

Since oligospermia has no symptoms associated, it is typically detected when the affected male has been trying to conceive for a long period of time without luck.

Fertility specialists can diagnose oligozoospermia using any of the following test options:

Semen analysis
Also called sperm test or seminogram, it is used to evaluate sperm parameters microscopically.
Bloodwork
It provides information about sex hormone levels and potential abnormalities.

Semen analysis

A semen analysis (SA) is the main diagnostic test used in Andrology labs to assess sperm quality. Aside from the sperm count, it also provides information on sperm motility, morphology, vitality, etc.

To perform a SA and maximize the accuracy of the results, about 3 to 5 days of sexual abstinence are required. Then, the sample is produced through masturbation at the fertility clinic for a lab test. The ejaculate is collected in a sterile container.

A semen sample is diagnosed with oligospermia when the sperm count is below 15 million sperm per milliliter.

A sperm sample is liquefied at the lab. Afterwards, the SA is carried out paying attention to two different levels:

Macroscopic analysis

Firstly, the semen is examined with the naked eye in order to evaluate the following parameter, always taking as a reference the guidelines of the World Health Organization (WHO):

  • Volume: over 1.5 ml
  • pH: between 7.2 and 8.0
  • Color: white or whitish gray, sometimes a bit yellowish
  • Consistency: sticky, jelly-like liquid, without lumps or strands
  • Liquefaction time: 20 minutes

If the volume of a semen sample is under 1.5 ml, it might be a case of hypospermia. This sperm disorder could aggravate oligospermia, since a reduced amount of semen correlates with a poor sperm count, too.

Fertility treatments, like any other medical treatment, require that you trust the fertility specialists that will be by your side during your journey. Logically, each clinic has a different work methodology. Our Fertility Report will offer you a selection of recommended clinics, that is, fertility centers that have passed our rigorous selection process. Moreover, our system is capable of comparing the costs and conditions of each one so that you can make a well-informed decision.

Microscopic analysis

Secondly, the sperm sample is examined under the microscope to see the characteristics of spermatozoa:

  • Count: more than 15 million/ml
  • Motility: more than 32% with progressive motility, or 40% with total motility
  • Morphology: 4% of sperm with normal shape
  • Vitality: 58% of live sperm
  • Leukocytes (WBCs): fewer than 1 million/ml

According to the WHO’s reference values, a man has a good sperm count if it is above 15 million/ml. Otherwise, the sample would be qualified as oligospermic.

Oligospermia may be accompanied by other seminal alterations. Thus, if both sperm count and motility are compromised, the diagnosis would be oligoasthenospermia. Conversely, if count and morphology present alterations, it would be a case of oligoteratozoospermia.

Hormonal analysis

Once oligospermia has been diagnosed with a SA, a blood test can help us find the cause behind it.

The main hormones that regulate male fertility are:

FSH
Produced by the pituitary gland, its function is to stimulate the production of sperm in the testicle. High FSH levels indicate that something is wrong with spermatogenesis and fewer sperms than expected are being produced. Normal FSH levels range from 1.0 to 12.0 mIU/ml.
Inhibin B
Produced in the testis, its function is to regulate spermatogenesis, causing FSH levels to diminish. Thus, too elevated inhibin B levels indicate that sperm production is occurring with normality. The normal inhibin B level is 140 pg/ml.

To sum up, there exists an inverse correlation between FSH and inhibin B levels.

Interpretation of results

Depending on the results of these hormones, we can expect any of the following outcomes:

Normal FSH and inhibin B levels
Sperm production occurs as expected. Thus, it might be a case of obstructive oligospermia: there may exist a blockage in the vasa deferentia, epididymis, or urethra.
Elevated FSH and decreased inhibin B levels
Defective spermatogenesis due to a reduced amount of stem cells in the testicle. It might be a case of secretory or non-obstructive oligospermia.
Decreased FSH and inhibin B levels
Defective oligospermia due to hormonal imbalances

A physical exploration is also indispensable in order to detect potential abnormalities in the testicles, including cryptorchidism, varicocele, etc.

Medical history

Finally, to conclude the interpretation of results, patients are asked to complete a form that helps the fertility specialists determine the cause of infertility.

Some interesting aspects that help the specialist to render an accurate diagnosis are:

  • For how long the patient has had infertility, and if there have been previous pregnancies or children born
  • Professional career and potential exposure to environmental toxic substances
  • Family history of genetic diseases or abnormalities
  • Medication intake
  • Lifestyle habits: diet, sports, tobacco, alcohol, etc.
  • Childhood diseases: parotitis or meningitis
  • Trauma, infections, surgical procedures…

Simply put, any data that may go unnoticed by the patient at first could turn out to be crucial for the diagnosis of oligospermia.

FAQs from users

What are the causes of a low sperm count in the ejaculate?

By Zaira Salvador BSc, MSc (embryologist).

It can be due to a number of causes that can cause oligospermia, and some of them are not easily detectable. Generally, they can be classified into pre-testicular, testicular, and post-testicular causes, based on whether there exists an alteration in the hormone levels, a testicular issue or blockage, respectively.

Read more: Causes of Oligospermia.

How many types of oligospermia exist?

By Zaira Salvador BSc, MSc (embryologist).

Based on the number of sperm under the reference value of 15 million sperm per milliliter, there exist three degrees of severity:

  • Mild oligospermia: 14-5 million/ml
  • Moderate oligospermia: 5-1 million/ml
  • Severe oligospermia: <1 million/ml

Learn more: Types of Oligospermia.

What is extreme or very severe oligospermia?

By Zaira Salvador BSc, MSc (embryologist).

Extreme or very severe oligospermia is diagnosed when the number of sperm per milliliter of ejaculated semen seen under the microscope is fewer than 1 million.

What symptoms are associated with low sperm count?

By Zaira Salvador BSc, MSc (embryologist).

There are no particular symptoms linked to oligospermia. There exist no visible or noticeable symptoms such as pain, which means males are unable to know they have oligospermia until they find out with a SA. In short, couples find it out when pregnancy does not occur after having been trying to conceive for a reasonable period of time and decide to undergo infertility testing.

Suggested for you

As mentioned above, a semen analysis is the most important of all lab tests for males. To get more info about this diagnostic test, see also: What Is a Semen Analysis Report? – Purpose, Preparation & Cost.

Based on the cause of oligospermia, the treatment of choice will be different. To get more info about this, read: Treatment of Oligospermia.

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References

Guzick DS, Overstreet JW, Factor-Litvak P, Brazil CK, Nakajima ST, Coutifaris C, et al. (2001). Sperm morphology, motility, and concentration in fertile and infertile men. N Engl J Med 2001; 345: 1388-1393.

McLachlan RI. Approach to the patient with oligozoospermia. J Clin Endocrinol Metab. 2013;98(3):873-80.

Sigman M, Zini A. (2009). Semen analysis and sperm function assays: what do they mean? Semin Reprod Med; 27: 115-123

World Health Organization (WHO) (1999). Laboratory manual of the WHO for the examination of human semen and sperm-cervical mucus interaction. Annali dell'Istituto Superiore di Sanita.

World Health Organization (WHO) (2010). WHO laboratory Manual for the examination of human semen and sperm-cervical mucus interaction. Cambridge Academic Press.

Read more

Authors and contributors

 Zaira Salvador
BSc, MSc
Embryologist
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia (UPV). Embryologist specializing in Assisted Procreation, with a Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). More information
License: 3185-CV
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