Oligospermia Explained
Oligospermia, more precisely called oligozoospermia, means the sperm concentration is lower than the laboratory reference range. WHO 2021 uses about 16 million sperm/mL as the lower reference value. The word describes a semen finding, not a final diagnosis. The important questions are how low the count is, whether it remains low on repeat testing, whether motility and morphology are also abnormal, and whether there is a correctable cause such as a clinical varicocele, hormone problem or testosterone/anabolic steroid suppression.
This page focuses on the medical term oligospermia and how it is used on a semen report. For a broader discussion of causes, treatment choices and chances of improvement, see the companion article ‘Low Sperm Count: Causes and Treatment.’
What is Oligospermia?
Oligozoospermia is a laboratory description of low sperm concentration. It may be mild, moderate or severe in everyday clinical language, although exact grading systems vary. Severe counts, especially below 5 million/mL, deserve greater attention because genetic and primary testicular causes become more common.
How to understand the report
| Finding | What it means |
|---|---|
| Concentration around/below 16 million/mL | Below the WHO 2021 lower reference value; interpret with total count and other parameters |
| Below 5 million/mL | Severe oligozoospermia; specialist evaluation and selected genetic testing may be relevant |
| Low count + low motility + poor morphology | Oligoasthenoteratospermia (OAT), a broader semen abnormality |
| Rare sperm only after centrifugation | Cryptozoospermia rather than ordinary oligozoospermia |
Common reasons
- Clinical varicocele.
- Recent fever or major illness.
- Primary testicular dysfunction or previous testicular injury.
- Exogenous testosterone or anabolic steroids.
- Hormonal disorders.
- Genetic causes in severe cases.
- Chemotherapy/radiotherapy or gonadotoxic exposure.
- Idiopathic male infertility with no specific cause found.
What tests may be needed
Persistent oligozoospermia is evaluated with history, physical examination and usually FSH/testosterone when clinically indicated. Severe cases may need karyotype or Y-chromosome microdeletion testing. Ultrasound is used selectively, not simply because the count is low.
Treatment and fertility options
Treat the cause where possible. Options may include stopping fertility-suppressing hormones, treating a clinical varicocele when appropriate, correcting a defined endocrine problem or proceeding to assisted reproduction when the semen deficit is not reversible or reproductive time is limited.
When oligospermia needs a structured male fertility work-up
- The sperm concentration is severely reduced or remains low on more than one properly collected semen analysis.
- Only rare sperm are seen, the result approaches cryptozoospermia, or a previous sample contained no sperm.
- FSH is high, the testes are small, or examination suggests a clinical varicocele or previous testicular damage.
- There is current or recent testosterone/anabolic steroid exposure, chemotherapy, or another medicine that may suppress sperm production.
- The severity may trigger genetic testing or materially change whether the couple should continue natural attempts, use IUI, or proceed to IVF/ICSI.
When should oligospermia be rechecked?
Sperm concentration varies between ejaculates. In a stable situation with an abnormal first result, the WHO 2025 infertility guideline suggests a repeat semen analysis after a minimum of about 11 weeks. A very low count, however, should trigger evaluation at the same time; the repeat test is not a reason to postpone hormones, examination or genetic assessment when indicated.
Why the word ‘oligospermia’ is not the diagnosis
Oligospermia tells you that sperm concentration is below a reference value; it does not explain why. The clinical meaning depends on how low the concentration is, whether the same pattern persists, semen volume, motility and morphology. A concentration that is only mildly below the reference range is very different from a count near the cryptozoospermia range.
Persistent severe oligozoospermia deserves assessment for testicular size and consistency, clinical varicocele, hormone abnormalities, previous testicular damage, medicines and genetic causes. Treatment is then directed at the cause and the couple’s fertility plan. There is no single tablet or supplement that is appropriate for every man whose report contains the word oligospermia.
The chance of natural conception cannot be estimated from concentration alone. Semen volume, progressive motility, total motile sperm available, duration of infertility and the female partner’s fertility all influence the practical meaning of an oligospermia result.
Because the term is descriptive, follow-up should focus on the cause and trend rather than whether the label itself disappears from the next report.
Emergency warning signs
Oligospermia is a laboratory finding, not an emergency. Acute severe testicular pain, new marked swelling, high fever with scrotal tenderness or major trauma needs urgent assessment because testicular torsion or infection can threaten the testis.
What to bring for consultation
Bring these if available:
- All semen reports with the actual sperm concentration, total sperm count and semen volume.
- FSH, LH and morning testosterone, especially when the concentration is severely reduced.
- Karyotype and Y-chromosome microdeletion results if genetic testing has already been advised.
- Scrotal Doppler or records of undescended testis, torsion, injury, varicocele or testicular surgery.
- Current medicines/testosterone/anabolic steroids and the couple’s fertility timeline.
FAQs
Is oligospermia the same as infertility?
No. It means low sperm concentration. Some men with oligozoospermia conceive naturally, while others need treatment or assisted reproduction.
Can oligospermia become azoospermia?
Depending on the cause, sperm production can fluctuate or worsen. Very low counts should be evaluated, and freezing sperm may be discussed in selected men at risk of losing ejaculated sperm.
Does severe oligospermia need genetic testing?
Often selected genetic testing is considered when the count is very low, especially with testicular atrophy or other evidence of impaired sperm production.
Can medicines increase the count?
Only in selected causes. Empirical “sperm tablets” are not a substitute for identifying hormonal, genetic, varicocele or medication-related causes.
Related reading
- Low Sperm Count: Causes and Treatment
- Semen Analysis Report Explained
- High FSH in Male Infertility
- Genetic Testing in Male Infertility
- Varicocele and 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