What Is Oligospermia? – Low Sperm Count Causes & Treatment

By (gynecologist), (embryologist), (urologist), (embryologist) and (psychologist).
Last Update: 12/21/2021

Oligozoospermia or oligospermia is a sperm pathology that leads to male infertility. It affects the sperm count, which appears diminished on a semen analysis report in comparison with the results of males with normal sperm count.

Oligospermia can be mild, moderate, or severe depending on the sperm count, that is, the number of sperms present in the ejaculate.

A semen sample is considered poor in terms of quality when the sperm count is too low or there are other pathologies such as poor sperm motility (asthenozoospermia), or sperm morphology defects (teratospermia).


Oligospermia, also called oligozoospermia, is defined as having a low sperm count in the ejaculate.

Oligospermic semen samples are considered of poor quality, and males diagnosed with oligospermia are likely to experience trouble conceiving due to the low amount of sperms able to reach the egg. A poor sperm count reduces the chances for spermatozoa to meet the egg cell inside the female reproductive tract and fertilize it.

According to the World Health Organization (WHO), oligospermia is diagnosed when the total sperm count is lower than 15 million spermatozoa per milliliter of ejaculate.

To learn more about the different ways to evaluate the quality of a semen sample at the laboratory and the reference values taken into consideration, we recommend that you visit the following guide: Measurement of Sperm Quality.

Diagnosis of oligospermia

Oligospermia doesn't have physical symptoms. Men with oligospermia are able to have sexual relations without problems and ejaculate normally. It is when they wish to have a child that, after failing to do so, tests are carried out and this alteration is found.

For the study of semen quality, a test called seminogram is performed to evaluate several semen parameters. One of these parameters is the sperm concentration which, as mentioned above, must be less than 15 million spermatozoa per milliliter to be considered oligospermia.

However, all the semen parameters analyzed in the semen analysis must be evaluated as a whole and taken into account in order to correctly estimate the quality of a semen sample.

Although the World Health Organization (WHO) has published an update of the Laboratory Manual for Semen Examination and Processing in 2021 (the sixth edition), the most common practice is to continue to follow the criteria of the fifth edition (2010).

In order to perform the semen analysis, semen samples must be collected by masturbation after 2 to 5 days of sexual abstinence. If this period of abstinence is not observed, the semen quality may be affected, and the diagnosis may not be correct.

You can find more detailed information about the diagnosis of this condition in this article: How is oligozoospermia diagnosed?


The causes of oligospermia are varied and can be classified into pre-testicular, testicular, and post-testicular factors.

Sometimes, finding the exact cause behind low sperm count is considerably complicated, since oligospermia can occur as a temporary alteration.

Pre-testicular causes

These are those related to problems with the endocrine, hormone system that regulates sperm production and spermatogenesis. This can occur due to hormonal levels that regulate the formation of spermatozoa, or due to external factors that act on our bodies.


Diet, tobacco and alcohol consumption, exposure to environmental toxins or stress are some of the external pretesticular factors that may influence low sperm production.

Testicular causes

When oligospermia derives from a testicular cause, it refers to alterations in the testicles. Among the most frequent testicular alterations are the following:

anomaly from birth in the male characterized by incomplete descent of one or both testicles.
accumulation of a large amount of fluid in the spermatic cord.
dilatation of the veins of the spermatic cord due to impaired blood circulation.

Some genetic alterations, such as microdeletions in the Y chromosome or trauma, also affect testicular function.

If you want to know about other sperm alterations that cause infertility in men, you can consult the following article: Male infertility due to sperm factor: causes and treatments.

Post-testicular causes

The low concentration of spermatozoa in the ejaculate due to a postesticular cause refers to problems in the expulsion of the spermatozoa to the exterior. Therefore, in this case there is sperm production, but the sperm do not leave the body.

The following are some of the postesticular causes that can lead to oligozoospermia:

Obstruction of the spermatic ducts
due to trauma or infection in the adjacent areas, which prevents the passage of spermatozoa.
Seminal infections
either in the prostate, epididymis, vas deferens or urethra.

If you want to learn more about this topic, we recommend you continue reading here: What are the possible causes of oligozoospermia?

Types of oligospermia

The type of oligospermia can be mild, moderate or severe, depending on whether the concentration of sperm in the ejaculated semen is higher or lower.

Mild oligospermia
when the number of spermatozoa found in the semen sample ranges between 14 and 5 million sperm per milliliter.
Moderate oligospermia
the sample contains between 5 and 1 million sperm/ml. Great improvements can be achieved in these cases following the proper treatment and a healthy lifestyle for a few months. The semen analysis would be repeated after a few months.
Severe oligospermia
Less than 1 million sperm/ml are found. Assisted Reproductive Technology (ART) is recommended to try for a baby.

For the diagnosis to be accurate, the specialist needs to evaluate several semen analyses done in different weeks. This helps to dismiss the possibility that low sperm count is associated with long abstinence periods or a temporary problem.

To learn more about the types of oligospermia you can access this article: Oligospermia types - mild, moderate and severe.


When the cause of oligospermia is unknown, leading a healthy lifestyle is the most appropriate treatment. This includes following a balanced diet, reducing or quitting toxic habits (alcohol or street drug consumption), and avoiding exposure to toxic environmental agents or toxic workplace habits.

There are certain natural remedies that may help to deal with oligospermia, including certain herbs to consume as herbal infusions like damiana, tribulus terrestris, Asian ginseng capsules, or maca root powder. Given that they are just home remedies, their effectiveness has not been scientifically proved.

As for the medications to treat oligospermia, there exist vitamin supplements or hormone doses that can help improve sperm production. Their accuracy, however, has not been proved yet. Vitamins E, C and B6 have a great number of antioxidants that protect the sperms from DNA fragmentation. Hormonal supplements are useful in patients with hormonal imbalances that affect the production of sperm, such as testosterone.

If no significant improvements are made, or if the causes of oligospermia are testicular or post-testicular, the best option to achieve pregnancy would be to seek the most adequate infertility treatment.

How to get pregnant

Although oligospermia is a major cause of male infertility, men with low sperm count are still able to produce sperms and expel them with ejaculation. In other words, natural conception is still possible. The chances, however, diminish eventually as the sperm count becomes lower.

For this reason, a fertility treatment could be the best option for those couples who find themselves in this situation. Learn more about it in the following section.

Assisted Reproduction Techniques (ART)

The chances of achieving a successful pregnancy with ART depend on the severity of oligospermia. Moreover, if it is accompanied by another sperm disease, the odds will be even lower.

In cases of mild oligozoospermia, pregnancy could be achieved with intrauterine insemination (IUI), a simple, cost-effective technique that usually offers good outcomes. To be able to undergo IUI, it is required that the sample contains at least 2-3 million motile sperm after being processed via sperm capacitation. It is required that the woman is 35 or less years of age, without female infertility issues.

If IUI is unsuccessful or in case you have been diagnosed with moderate or severe oligospermia, the treatment of choice would be in vitro fertilization (IVF), either the classical type or IVF/ICSI.

If you need to undergo IVF to become a mother, we recommend that you generate your Fertility Report now. In 3 simple steps, it will show you a list of clinics that fit your preferences and meet our strict quality criteria. Moreover, you will receive a report via email with useful tips to visit a fertility clinic for the first time.

The steps to follow in a process of classical IVF or IVF/ICSI are quite similar—the woman receives ovarian stimulation treatment to produce multiple eggs, which are harvested from her ovaries by means of follicle puncture. Afterward, fertilization is done in the laboratory.

In cases of severe oligospermia, ICSI is more effective than classical IVF, as only a single sperm cell would be necessary for fertilization to occur successfully.

FAQs from users

If I have mild oligozoospermia, can I give artificial insemination a try?

By Concha Leal Cariñena M.D. (gynecologist).

Yes, as long as the number of mobile spermatozoa (REM) is greater than 5x10 spermatozoa/ml, but it will also depend on other factors such as the age of the woman or the time of sterility.

Why is oligozoospermia a cause of infertility?

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

Men with alterations in seminal parameters suffer from male infertility due to the inability to conceive.

In the case of oligozoospermia, as there is a lower number of sperm in the ejaculate, there is less chance that these can ascend through the female reproductive tract to the uterus and fallopian tubes, and reach the egg to achieve a natural pregnancy.

Is 'oligospermia' the same as 'azoospermia'?

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

No, although oligospermia refers to the low concentration of spermatozoa, they are present in the ejaculate. Azoospermia is the absence of spermatozoa in the ejaculated semen, and invasive techniques are necessary for their recovery, such as epididymal aspiration, testicular puncture or biopsy.

What are the symptoms of oligospermia?

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

Oligospermia does not have any kind of symptoms such as pain that a man can perceive. A man can have oligospermia and never realize it, unless he wants to have a child and does not succeed. If the oligospermia is due to a pathology such as cryptorchidism or varicocele, these can be seen with the naked eye.

Can oligospermia be treated?

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

Yes, as explained above, men with a diagnosis of oligospermia can still have genetic children. If it's a case of mild oligospermia, they can conceive naturally or by means of IUI. In moderate and severe cases, pregnancy could be achieved with IVF or IVF/ICSI.

Read: What Is In Vitro Fertilization (IVF)? – Process, Cost & Success Rates.

Is there any oligospermia prevention treatment?

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

The best way to maintain good seminal quality and the male's fertile potential is to practice healthy lifestyle habits, eat a healthy and balanced diet, not consume drugs, alcohol and tobacco, practice sports to keep in shape, etc.

Suggested readings

The only accurate test available today to evaluate whether a man is fertile or not is the semen analysis or seminogram. The WHO has established a series of reference values for parameters such as concentration, motility, and morphology in order to evaluate the quality of a semen sample. Want to learn more about this crucial test? Check this out: What is a Semen Analysis Report?

To learn more about male infertility testing, visit the following guide: Male Fertility Testing – How Do You Know if a Man’s Sperm Is Fertile?

Oligospermia is a sperm disorder that is defined as low sperm count. But there exist other sperm disorders depending on the parameter that is affected. Find them out here: Sperm Disorders that Cause Male Infertility.

Also, the following is a complete guide to fertility treatment options where you will find everything you need to know about IVF and other treatments. Read: What Are Infertility Treatments? – Definition, Types & Costs.

We make a great effort to provide you with the highest quality information.

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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.

Kirby EW, Wiener LE, Rajanahally S, Crowell K, Coward RM. Undergoing varicocele repair before assisted reproduction improves pregnancy rate and live birth rate in azoospermic and oligospermic men with a varicocele: a systematic review and meta-analysis. Fertil Steril. 2016;106(6):1338-1343.

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

Meistrich ML. Effects of chemotherapy and radiotherapy on spermatogenesis in humans. Fertil Steril. 2013;100(5):1180-6.

Sermondade N, Faure C, Fezeu L, Lévy R, Czernichow S; Obesity-Fertility Collaborative Group. Obesity and increased risk for oligozoospermia and azoospermia. Arch Intern Med. 2012;172(5):440-442.

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: 'If I have mild oligozoospermia, can I give artificial insemination a try?', 'Why is oligozoospermia a cause of infertility?', 'How often should you have intercourse with low sperm count?', 'Is 'oligospermia' the same as 'azoospermia'?', 'Is having low sperm count hereditary?', 'What are the symptoms of oligospermia?', 'Can oligospermia be treated?', 'Can low sperm count lead to miscarriage?', 'Is there any oligospermia prevention treatment?', 'When does sperm count decrease with age?', 'How long would it take to get pregnant with low sperm count?', 'Can low sperm count cause quick ejaculation?' and 'Can low sperm count cause erectile dysfunction?'.

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Authors and contributors

 Concha Leal Cariñena
Concha Leal Cariñena
Bachelor's Degree in Medicine from the University of Zaragoza. She has an extensive career as a gynaecologist specialising in assisted reproduction and is also an associate lecturer in the Department of Surgery, Gynaecology and Obstetrics at the University of Zaragoza More information about Concha Leal Cariñena
License: 5008547
 Marta Barranquero Gómez
Marta Barranquero Gómez
B.Sc., M.Sc.
Graduated in Biochemistry and Biomedical Sciences by the University of Valencia (UV) and specialized in Assisted Reproduction by the University of Alcalá de Henares (UAH) in collaboration with Ginefiv and in Clinical Genetics by the University of Alcalá de Henares (UAH). More information about Marta Barranquero Gómez
License: 3316-CV
 Ricardo García Navas
Ricardo García Navas
He graduated in Medicine from the Complutense University of Madrid, specializing in Urology via MIR at the Ramón y Cajal University Hospital. Dr. Garcia Navas has a long career in the field of urology and, in addition, currently also works as a fertility specialist urologist. More information about Ricardo García Navas
Member number: 282854749
 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:
 Cristina  Algarra Goosman
Cristina Algarra Goosman
B.Sc., M.Sc.
Graduated in Psychology by the University of Valencia (UV) and specialized in Clinical Psychology by the European University Center and specific training in Infertility: Legal, Medical and Psychosocial Aspects by University of Valencia (UV) and ADEIT.
More information about Cristina Algarra Goosman
Member number: CV16874

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