Male infertility: causes, tests and treatment
Male factor is involved in a substantial proportion of cases where a couple has difficulty conceiving. A semen analysis is quick, inexpensive and non-invasive — and it should be among the first tests, not a later one. Assessment of the male partner is still frequently delayed.
The tests
Semen analysis measures volume, sperm concentration, total number, motility and morphology.
WHO 6th edition (2021) lower fifth percentile values:
| Parameter | Value |
|---|---|
| Semen volume | 1.4 mL |
| Concentration | 16 million/mL |
| Total sperm number | 39 million per ejaculate |
| Total motility | 42% |
| Progressive motility | 30% |
| Vitality | 54% |
| Normal forms | 4% |
What those numbers are not. WHO states plainly that the lower fifth percentile "does not represent a limit between fertile and infertile men", and that there is substantial overlap between fertile and infertile men. These describe where 95% of men who conceived naturally within a year fell — not a pass mark.
Check which edition your laboratory used. The 5th edition (2010) figures differ and are still widely quoted.
Hormonal tests. FSH and testosterone are not first-line for every man, but are indicated with impaired libido, erectile dysfunction, low or absent sperm count, atrophic testes, or signs of hormonal abnormality. Add LH where testosterone is below 300 ng/dL, and prolactin for reduced libido.
Genetic tests. Karyotype and Y-chromosome microdeletion analysis where there is azoospermia, or severe oligozoospermia under 5 million/mL with raised FSH or testicular atrophy. CFTR testing including the 5T allele where there is absent vas deferens or unexplained obstructive azoospermia.
Not part of initial evaluation: sperm DNA fragmentation, antisperm antibodies, or routine diagnostic testicular biopsy.
One number tells you little
The guideline is clear: results are of greatest clinical significance when multiple abnormalities are present. Except for azoospermia, complete globozoospermia, necrozoospermia and complete asthenozoospermia, no single parameter is highly predictive.
Repeat before concluding — parameters vary substantially between samples.
Treatment
Varicocele repair — consider where a varicocele is palpable and semen parameters are abnormal and the couple is infertile. Not recommended for non-palpable varicoceles found only on imaging — a strong recommendation against.
Azoospermia — extended search of the centrifuged sample finds rare sperm in up to 35% of men previously called azoospermic. Where none are found, microdissection TESE is recommended for non-obstructive azoospermia. Genetic testing first: complete AZFa or AZFb deletion means sperm have not been retrieved by TESE, so surgery is not indicated.
Testosterone — for a man interested in current or future fertility, testosterone monotherapy should not be prescribed. It suppresses sperm production and can cause azoospermia.
Supplements — a Cochrane review of 90 trials found a possible live birth benefit that disappeared when high-risk-of-bias studies were removed. Evidence rated very low certainty and described as inconclusive.
Timescale
Sperm production takes roughly 72 to 90 days. Allow three months before repeating any test after a change.
Sources
- WHO laboratory manual, 6th edition (2021)
Frequently Asked Questions
What is the most common cause of male infertility?▾
Varicocele is the most common single identifiable and correctable cause — found in 35% of infertile men. Idiopathic oligospermia (no identified cause) is the most common overall category. Among genetic causes, Klinefelter syndrome is most common in azoospermia and Y-chromosome microdeletions in severe oligospermia.
Can male infertility be cured?▾
Many causes are treatable. Varicocele can be surgically corrected. Hypogonadotropic hypogonadism responds well to FSH/hCG treatment. Obstructive azoospermia has >90% sperm retrieval success. Even non-obstructive azoospermia has 40–60% success with micro-TESE. Lifestyle-related oligospermia improves significantly with change. Only severe genetic testicular failure is irreversible — but even then, ICSI with surgically retrieved sperm is often possible.
How long does male infertility treatment take?▾
Timeline varies by cause. Lifestyle changes take 3 months to show effect in semen analysis. Varicocele surgery shows improvement at 3–6 months post-operation. Hormonal treatment for HH takes 6–12 months for sperm to appear. Always retest with a semen analysis 3–4 months after any intervention.