Low Sperm Count Overview

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Low Sperm Count Overview

Updated: 28-November-2022


Low sperm count, also known as oligospermia or oligozoospermia, happens when a man has 15 million or less sperm per millilitre (mL) of semen.

There are 3 forms of oligospermia:

  • Mild oligospermia (10-15 million sperm/mL)
  • Moderate oligospermia (5-10 million sperm/mL)
  • Severe oligospermia (< 5 million sperm/mL)

According to the World Health Organization reference values, only 5% of males with mild oligospermia achieve a ‘time to pregnancy’ of less than 12 months with their partner.

Source: Cooper T G, et al. (2009)

In couples seeking treatment, where male factors is the sole cause of infertility, low sperm count accounts for 8 out of 10 cases. However, due to underreporting and a lack of high quality studies, the exact prevalence among the wider community is not known.

In general, adult sperm count is by and large pre-set during early infancy (3 months of age). However, post-puberty, semen volume and sperm motility, along with the quantity and quality of sperm gradually declines with age, while oxidative stress levels increase.

Interestingly, the male body continues to produce sperm, well past the age of 80. At this point in life though testicular volume and NAD+ levels begin to decrease leading to a rapid decline in spermatogenesis and overall fertility.

In infertile males this rapid decline seems to occur much sooner.

With a significant drop in progressive sperm motility, morphology and vitality beginning around 35 years of age. This makes age a critical factor for men diagnosed with some form of infertility.


The first test for infertility in ones husband is semen analysis. Using the WHO reference values, a semen value in the 5th percentile (5% of males to conceive within 12 months of intercourse), is considered abnormal & also infertile after 12 months trying to conceive, where no female factors exist.

Initial semen analysis of low sperm count is then confirmed by repeating the test 3 months later. This allows spermatogenesis, the biological process where sperm develop from germ cells in the testis, to repeat one full cycle.

However semen analysis fails to pinpoint the cause of low sperm count.

The male reproductive system itself is regulated by a complex network of positive and negative feedback loops, beginning at the hypothalamus in the brain which releases gonadotrophin-releasing hormone (GnRH) in a pulsatile manner.

GnRH causes the secretion of gonadotrophins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), from the anterior pituitary gland which stimulate the (Leydig, Sertoli) cells in the testis, to produce sex steroids and inhibin, and in turn apply negative feedback to GnRH, LH and FSH secretion.

Any disruption to this network directly impairs the function of the testis, which is to synthesize testosterone and carry out spermatogenesis.

Interestingly the loss of one or both of these functions, known as male hypogonadism, is commonly found in 4 out of 10 men with oligospermia.

Hypogonadism itself can be further diagnosed as primary hypogonadism or secondary hypogonadism.

Primary hypogonadism is when the testes are mostly affected, causing lower testosterone concentrations in serum, impaired spermatogenesis and an increase in gonadotrophins.

Secondary hypogonadism (also called hypogonadotropic hypogonadism) is defined by low testosterone concentration in serum, reduced spermatogenesis and low or abnormal levels of gonadotrophins.

Although low levels of testosterone (TT < 264ng/dL) was not significantly linked to impaired semen parameters, in a recent study of males with total sperm count > 5 million requiring further investigation (studies).

Primary hypogonadism and secondary hypogonadism can both be caused by congenital disorders or acquired after birth.

In acquired cases of secondary hypogonadism, such as obesity, high levels of exercise can also cause an increase in inflammation, resulting in no improvement of gonadotrophin or testosterone levels and thus no change in sperm quality.

Overall the hypothalamic-pituitary-testis (HPT) axis in males is finely balanced with changes in energy balance, between exercise and inflammation, regulating the expression of kisspeptin, which controls the levels of GnRH (gonadotropin-releasing hormones), LH, FSH and testosterone.


Sperm cell production, also known as spermatogenesis, is a complex process involving several organs, mainly the testicles and two glands (hypothalamus and pituitary) in the brain.

This process occurs in 3 distinct phases after puberty, in which mature sperms cells are produced from primordial germ cells.

Phase 1 (Spermatocytogenesis)

During this phase, also known as the mitotic or proliferative phase, dark spermatogonia which are undifferentiated stem cells, go through mitosis to produce more stem cells, among those dark spermatogonia, some differentiate into pale spermatogonia that further differentiate into B spermatogonia.

Phase 2 (Spermatidogenesis)

In this (meiosis) phase, B spermatogonia leave the basement membrane of the seminiferous tubule, pass through the blood-testis barrier and divide into 2 primary spermatocytes each.

Two sequential meiotic divisions then follows:

  • Each primary spermatocytes divides into 2 secondary spermatocytes
  • Each secondary spermatocytes divide into 2 spermatids.

Phase 3 (Spermiogenesis)

Each spermatid then differentiate into a mature spermatozoon. The body produces around 100 million mature sperm cells each day.

The whole process of spermatogenesis takes around 74 days to be completed and a further 12 to 21 days is needed for the sperm to travel from the epididymis to the ejaculatory ducts.

Therefore, it takes approximately 3 months for any changes to be reflected in the ejaculated sperm.

Symptoms of Low Sperm Count

The main sign of low sperm count in a male is the inability to conceive a child despite 1 year of frequent and unprotected intercourse.

The inability to conceive despite 1 year of frequent and unprotected intercourse is defined as infertility in a couple.

Other symptoms may include:

  • Low sex drive or erectile dysfunction
  • Swelling, lump and pain in the testicular area
  • Low facial or body hair

Risks Associated with Low Sperm Count

Men suffering from low sperm count are susceptible to further issues such as:

  • Stress, loss of self-esteem and relationship issues due to difficulties trying to conceive.
  • Increased risk of cancer.


Several studies undertaken have linked low sperm count to a higher risk of cancer. Although, no cause-and-effect relationship was directly established, infertile men should consult their Doctor to discuss long-term monitoring strategies.

Causes of Low Sperm Count

The causes of low sperm count fall into 3 main categories:

  • Medical
  • Environmental
  • Lifestyle

Diagnosis of Low Sperm Count

The inability to conceive despite 1 year of frequent and unprotected intercourse is defined as infertility in a couple. At this stage, it is advised that both partners consult a Doctor since the inability to conceive frequently occurs due to a combination of male and female issues.

For males partners at this initial consultation, the European Academy of Andrology recommends Doctors perform the following:

  • General physical examination to assess for signs of hypogonadism.
  • Physical examination of the scrotum to assess: the volume and consistency of the testicles and epididymis, the total or partial absence of deferent ducts, and the presence of varicoceles.
  • Two semen analyses (3 months apart) according to the WHO guidelines.

Semen analysis evaluates both the quantity and quality of sperm.

Semen samples can be collected in the clinic or at home following 2 to 7 days of sexual abstinence. However, if collected at home, the sample should be kept at room temperature and delivered to the laboratory within 1 hour for accuracy. The test should then be repeated after 3 months to confirm any abnormal values.

Males with borderline results should request a third semen analysis to potentially avoid unnecessary treatment.

Source: Aznavour Y, et al. (2022)


Some home-testing kits to detect low sperm count are available for over the counter use.

These kits however can not duplicate the accuracy or range of sperm parameters, measured within an accredited laboratory, and should therefore be interpreted with caution.

Interpreting Test Results

The following table outlines the lower reference limits published by the WHO for semen analyses. Any value below these lower limits is considered abnormal. Therefore, a sperm count less than (or equal to) 39 million is diagnosed as low sperm count.

Sperm parameterLower limit95% Confidence Interval
Volume1.5mL1.4 – 1.7 mL
Sperm concentration15 million/mL12 – 16 million/mL
Total sperm number39 million33 – 46 million
Morphology (Tygerberg method)4% normal form3 – 4% normal form
Vitality58% live55 – 63%
Progressive motility32%31 – 34%
Total (progressive and non-progressive) motility40%38 – 42%

Based on the initial results, the Doctor might need to undertake additional tests to determine the cause of low sperm count.

These additional tests may include:

  • Scrotal ultrasound to look at the testicles and surrounding tissues.
  • Transrectal ultrasound to check for any blockages in the ejaculatory ducts and seminal vesicles.
  • Post-ejaculation urinalysis to check for retrograde ejaculation. This happens when the sperm cells travel backwards into the bladder during ejaculation.
  • Blood tests to check the level of hormones secreted by the testicles and pituitary gland or signs of genetic abnormality.
  • Other less common tests:
    i) Biopsy of the testicles to evaluate if there is normal production of sperm.
    ii) Anti-sperm antibody tests to check if the immune system is attacking the sperm cells.
    iii) Specialized sperm function tests to determine the penetration strength or attaching potential of the sperm cells.

Treatment of Low Sperm Count

The initial advice of physicians for males diagnosed with low sperm count is to keep trying, by having intercourse every 1-2 days during the woman’s fertile window, as a significant proportion of couples manage to conceive naturally in the preceding 12 months.

In fact, studies consistently show that ejaculatory abstinence beyond 24 hours significantly decreases sperm count in males diagnosed with oligospermia.

However, depending on the physicians initial findings, they may also recommend you begin one of several treatment options.

Treatment options for men with low sperm count include: lifestyle, supplements, environment, surgery, medication and Assisted Reproductive Technology.


Low sperm count can be reversed in some acquired cases of the condition, such as those caused by obesity, smoking, recreational drugs & steroid use. However in cases of low sperm count caused by congenital disorders or cancer treatments (chemotherapy, gonadotoxins) low sperm count cannot be cured.


Causes of Low Sperm Count

Causes of Low Sperm Count

The causes of low sperm count fall into 3 main categories: medical, environmental and lifestyle. Medical causes of low sperm count include…. Read more

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