A low sperm count means the concentration of sperm in semen is below the laboratory reference range. WHO 2021 lists about 16 million sperm/mL as the lower reference value, but fertility does not suddenly change at that number. A mildly low count can still be compatible with natural conception, while a very low or repeatedly low count needs a cause-based male fertility evaluation. Common reasons include varicocele, recent fever, hormonal or testicular problems, genetic conditions, testosterone or anabolic steroid use, previous testicular damage and sometimes no identifiable cause.

What does low sperm count mean?

Low sperm count is usually called oligozoospermia or oligospermia. The laboratory reports sperm concentration in millions per millilitre, but the total number of sperm in the entire ejaculate is also important. A low concentration in a large-volume sample and the same concentration in a tiny-volume sample do not carry the same practical meaning. WHO reference values are population reference limits rather than a biological dividing line between fertile and infertile men.

Common causes of low sperm count

• Recent high fever or significant systemic illness.
• Clinical varicocele.
• Exogenous testosterone or anabolic steroid use.
• Previous undescended testis, torsion, trauma, testicular surgery, chemotherapy or radiotherapy.
• Primary testicular dysfunction, often associated with raised FSH.
• Pituitary/hypothalamic hormonal disorders, usually with low or inappropriately normal gonadotropins.
• Genetic causes, especially when the count is very low or absent.
• Some medicines, smoking, obesity, metabolic disease and environmental or occupational exposures.
• Sometimes no clear cause is found despite appropriate evaluation.

How the result is confirmed

If the first semen analysis is abnormal, check whether the complete sample was collected and whether there was recent fever or another temporary factor. WHO 2025 suggests repeating an abnormal semen analysis after at least about 11 weeks in most stable situations. Severe oligozoospermia may justify earlier specialist evaluation while the repeat test is being planned. Examination, FSH/testosterone and selected genetic tests are added according to severity and clinical findings.

Does this result mean infertility?

No single semen parameter by itself can reliably label a man fertile or infertile. The chance of pregnancy depends on the severity and persistence of the abnormality, other semen parameters, sexual timing and the female partner’s fertility. A pattern involving several abnormal parameters is usually more clinically important than one mildly abnormal value.

Treatment depends on the cause

Treatment is not a single “sperm count medicine.” A palpable varicocele with infertility and abnormal semen may be treated surgically in selected men. Hormonal deficiencies are treated according to the endocrine pattern. Testosterone or anabolic steroids may need to be stopped under medical supervision. Obstruction, if present, is managed differently from impaired production. If the count remains low, the couple may discuss natural conception, IUI or IVF/ICSI based on total motile sperm count and female factors.

What not to do

• Do not start testosterone to “increase strength” while trying for pregnancy; it can suppress sperm production.
• Do not assume that one low report is permanent.
• Do not take antibiotics unless there is evidence of infection.
• Do not spend months on supplements while ignoring severe oligozoospermia, small testes or a palpable varicocele.
• Do not judge fertility from concentration alone; total motile sperm count and partner factors matter.

When low sperm count needs specialist evaluation

• The sperm concentration is markedly low, falling, or remains below the reference range on repeat testing.
• The report is near the cryptozoospermia range, only rare sperm are seen, or a previous sample showed azoospermia.
• Examination suggests a palpable varicocele, small testes, previous undescended testis, torsion, injury, cancer treatment or testicular surgery.
• You currently use testosterone or anabolic steroids, or recently stopped them while trying for pregnancy.
• The couple has prolonged infertility, the female partner has limited reproductive time, or previous IUI/IVF treatment has failed.

What matters more than one sperm-count number

Sperm concentration is only one part of the semen analysis. The total sperm number also depends on semen volume, and the number of moving sperm depends on motility. In practical fertility planning, a urologist therefore looks at the whole sample, the trend across repeat tests and, when useful, the total motile sperm count rather than treating 16 million/mL as a simple pass-or-fail line. Two men with the same concentration can have very different fertility potential if their volume and progressive motility are different.

A persistently very low count deserves a more structured work-up than a mildly low isolated result. Examination of the testes and vas deferens, FSH/LH/testosterone, review of fever and medicines, and assessment for a clinical varicocele may identify a cause. Genetic testing is considered in selected men with severe oligozoospermia or other signs of impaired sperm production. This is why months of supplements alone are not a sensible first strategy when the count is extremely low.

Semen results also fluctuate with abstinence, recent illness and ordinary biological variation. If the first count is only mildly low, a repeat high-quality sample can prevent overdiagnosis. If the count is extremely low, however, the repeat test should happen alongside evaluation rather than becoming a reason to postpone it.

What to bring for consultation

Bring these if available:

• All semen reports showing concentration, total sperm count and semen volume.
• Abstinence duration, whether the full sample was collected, and any fever/major illness in the previous 3 months.
• FSH, LH and morning testosterone; bring karyotype/Y-microdeletion results if the count is very low and testing was done.
• Scrotal Doppler or records of undescended testis, torsion, testicular injury or previous groin/scrotal surgery.
• Current medicines, supplements, testosterone/anabolic steroids and the couple’s fertility timeline.

FAQs

Related reading

• Semen Analysis Report Explained
• Oligospermia Explained
• Hormonal Tests for Male Infertility
• High FSH in Male Infertility
• Genetic Testing in Male Infertility
• Urologist in Latur

References

• World Health Organization. WHO laboratory manual for the examination and processing of human semen, 6th ed https://www.who.int/publications/i/item/9789240030787
• World Health Organization. Guideline for the prevention, diagnosis and treatment of infertility. 2025 https://www.who.int/publications/i/item/9789240115774
• European Association of Urology. EAU Guidelines on Sexual and Reproductive Health: Male Infertility. 2026 https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-infertility
• American Urological Association/American Society for Reproductive Medicine. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline (2020; Amended 2024) https://www.auanet.org/documents/Guidelines/PDF/2024%20Guidelines/Male%20Infertility%20Unabridged%20Final.pdf