The different grades of oligozoospermia: mild, moderate and severe

By (gynecologist), (embryologist), (biochemist) and (fertility counselor).
Last Update: 12/04/2018

Oligozoospermia can be defined as having a low sperm count in the ejaculated semen.

A sperm count that is below 15 million sperm per milliliter is considered as oligozoospermic based on the guidelines published by the World Health Organization (WHO). Nonetheless, oligozoospermia can be classified into three groups depending on its severity:

  • Mild oligospermia
  • Moderate oligospermia
  • Severe oligospermia

The degree of oligospermia is diagnosed using a test called semen analysis, seminogram, or sperm test, in which the number of sperm is counted under a microscope.

Mild oligospermia

This is the least severe of all types of oligospermia. The sperm count of these patients ranges between 14 and 5 million spermatozoa per milliliter.

Since normal values are above 15 million sperm per ml, a natural pregnancy might be possible with mild oligospermia, although it might take longer. Moreover, it would depend on sperm motility as well.

Should reproductive technologies be required, males affected with mild oligospermia can give Intrauterine Insemination (IUI) a try, which is the simplest, cheapest of all treatment options. For IUI to be possible, the Motile Sperm Count (MSC) must be higher than 3 million sperm after sperm capacitation.

Moderate oligospermia

With moderate oligospermia, the number of sperm per milliliter is even lower than with the mild type. Particularly, these males have a sperm count that ranges between 5 and 1 million sperm per milliliter.

Normally, patients with mild-to-moderate oligospermia are referred to a medical treatment that helps them improve their sperm quality. Also, following a healthy, balanced diet, and taking vitamin supplements with antioxidants is strongly recommended.

Considering seeing a fertility specialist? Don't forget that, in the field of Reproductive Medicine, as in any other medical area, it is crucial that patients rely on the doctors and staff that will help them through their treatment cycle. Logically, conditions vary from clinic to clinic. For this reason, we recommend that you generate your Fertility Report now. It will offer you a list of clinics that have passed our rigorous selection process successfully. Furthermore, the system will make a comparison between the fees and conditions of each clinic so that you can make a better-informed decision.

After a few months, the semen analysis should be repeated to evaluate the sperm parameters again, since oligospermia may have improved or even disappeared.

Unfortunately, oligospermia does not go away by itself in all cases, or if it does, infertility may continue due to other causes. In these cases, the patient and his partner may have no choice but to undergo In Vitro Fertilization (IVF).

Severe oligospermia

Extreme or severe oligospermia is the most serious type of oligospermia, and the one with the worst prognosis. The sperm count is fewer than 1 million sperm per milliliter.

Achieving a pregnancy naturally is almost impossible with severe oligospermia. The good news is that, with the latest advancements in the field of Assisted Procreation, these males can become fathers thanks to techniques such as Intracytoplasmic Sperm Injection (ICSI).

With ICSI technique, the only requirement is to find at least one live sperm under the microscope to inject it into the egg cell and make fertilization possible.

FAQs from users

How can pregnancy be achieved with severe oligospermia?

By Miguel Angel Checa Vizcaino M.D., Ph.D. (gynecologist).

Severe oligospermia is a very significant decrease in the number of sperm that makes spontaneous gestation impossible, as well as the fertilization of eggs in the laboratory using conventional in vitro fertilization (IVF) techniques.

In order to perform in vitro fertilization, at least 50,000-100,000 spermatozoa are necessary. When the number of spermatozoa is lower than this value, it is very difficult for a natural fertilization of the eggs to take place.

Therefore, in cases of severe oligospermia with a sperm count below 100,000, IVF with ICSI (Intracytoplasmic Cytoplasmic Sperm Injection) is performed.

Is there a cure for moderate oligospermia?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Yes, as long as the cause is related to hormones. For example, low testosterone levels. In such case, your doctor will prescribe you a hormonal therapy.

On the other hand, if oligospermia is due to a testicular cause such as varicocele, surgery might be required to recover testicular function.

Are severe oligospermia and azoospermia the same?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

No. Even in the most severe cases of oligospermia, a handful of sperm can be found in the semen analysis. Conversely, azoospermia means that the sperm count is zero.

For pregnancy to be possible with azoospermia, a testicular biopsy is required to see if retrieving sperms directly from the testicle is possible or not. If it isn't, the only option to become a father is using donor sperm.

What does it mean to have discrete oligozoospermia?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

The term discrete refers to oligospermia that does not deviate much from the value considered normal. Therefore, this type corresponds to a mild oligozoospermia, with a value close to 15 million spermatozoa per milliliter.

My semen analysis indicates that I have pure oligospermia, what does this mean?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Pure oligozoospermia means that no other alterations have been found in the seminal parameters of the spermiogram. That is, the patient is only affected by the number of spermatozoa in the ejaculate. Other values, such as motility and morphology, are normal.

The treatment of oligospermia depends fundamentally on the cause. If you want to learn more about this, read: Treatment of Oligospermia.

Oligozoospermia can be classified into secretory/non-obstructive and obstructive based on what is causing it. To get more info, see also: What Are the Potential Causes of Oligospermia?

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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.

Meseguer M, Garrido N, Martinez-Conejero JA, et al. Relationship between standard semen parameters, calcium, cholesterol contents, and mitochondrial activity in ejaculated spermatozoa from fertile and infertile males. Journal of assisted reproduction and genetics. 2004;21: 445-451

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

FAQs from users: 'How can pregnancy be achieved with severe oligospermia?', 'Is there a cure for moderate oligospermia?', 'Are severe oligospermia and azoospermia the same?', 'What does it mean to have discrete oligozoospermia?' and 'My semen analysis indicates that I have pure oligospermia, what does this mean?'.

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Authors and contributors

 Miguel Angel Checa Vizcaino
Miguel Angel Checa Vizcaino
M.D., Ph.D.
Dr. Miguel Angel Checa has a degree in Medicine and Surgery and a doctorate in Pediatrics, Obstetrics and Gynecology, Preventive Medicine and Public Health from the Autonomous University of Barcelona. More information about Miguel Angel Checa Vizcaino
Zulassungsnummer: 080830513
 Zaira Salvador
Zaira Salvador
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) More information about Zaira Salvador
License: 3185-CV
Adapted into english by:
 Michelle Lorraine Embleton
Michelle Lorraine Embleton
B.Sc. Ph.D.
PhD in Biochemistry, University of Bristol, UK, specialising in DNA : protein intereactions. BSc honours degree in Molecular Biology, Univerisity of Bristol. Translation and editing of scientific and medical literature.
More information about Michelle Lorraine Embleton
 Sandra Fernández
Sandra Fernández
B.A., M.A.
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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