The different grades of oligozoospermia: mild, moderate and severe

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.

Diagnosis of the type of oligospermia

Oligospermia, also called oligozoospermia, is a seminal disorder in which the sperm count and concentration in the male ejaculate is affected.

According to the criteria of the World Health Organisation (WHO), oligospermia is considered to be a sperm concentration below 15 million per millilitre of semen.

The test that allows the diagnosis of oligozoospermia and its degree is the semen analysis. This is a semen analysis in which macroscopic parameters (volume, colour, pH, etc.) and microscopic parameters (such as sperm concentration, motility and morphology) are evaluated.

In any case, all these parameters must be evaluated and interpreted together to make a better estimation of semen quality

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.

Normozoospermia vs. mild oligozoospermia

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.

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

Normozoospermia vs. moderate oligozoospermia

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.

Normozoospermia vs. severe oligozoospermia

At this point, it is important to mention that if the concentration of spermatozoa is less than 100,000/ml of semen, this seminal alteration is called cryptozoospermia. On the other hand, if no spermatozoa are found in the ejaculated semen, it is determined that the male has azoospermia.

FAQs from users

How can pregnancy be achieved with severe oligospermia?

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?

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?

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?

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?

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.

Recommended reading

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?