Male factor infertility — defined broadly as a contribution from sperm quality or quantity to a couple's difficulty conceiving — accounts for approximately 30–40% of all fertility problems seen at UK fertility clinics. In a further 20–30% of cases, both male and female factors are identified. It is the single most common diagnosable cause of infertility in couples.

Despite this, male factor infertility is frequently under-investigated compared to female factors, and the experience of male partners in fertility treatment is often underacknowledged. This guide explains the clinical picture, what testing looks like, and how IVF — specifically with intracytoplasmic sperm injection (ICSI) — addresses male factor cases.

Common Causes of Male Factor Infertility

Low sperm count (oligozoospermia). The World Health Organisation reference range for normal sperm concentration is 16 million/mL or above. Counts below this are classified as oligozoospermia; severe oligozoospermia is typically defined as under 5 million/mL, and counts under 1 million/mL as extreme oligozoospermia.

Poor motility (asthenozoospermia). Total motility below 42% or progressive motility below 30% is classified as below normal. Sperm that cannot swim effectively are less able to reach the egg in natural conception, though this matters less in IVF where sperm are placed directly with the egg.

Poor morphology (teratozoospermia). The proportion of sperm with normal shape. Normal morphology by Kruger strict criteria is 4% or above. Morphology in isolation is less predictive of outcome than count and motility.

Azoospermia. Complete absence of sperm in the ejaculate. This is classified as obstructive (sperm are produced but cannot be ejaculated, typically due to blockage) or non-obstructive (production is impaired). Both can be addressed surgically, as described below.

Retrograde ejaculation. Semen travels backwards into the bladder rather than forwards at ejaculation. Sperm can be retrieved from urine for use in treatment.

Genetic causes. Y chromosome microdeletions and Klinefelter syndrome are among the genetic causes of severe male factor infertility. Genetic testing may be recommended before ICSI in some cases.

Semen Analysis: What It Measures

A semen analysis is the primary diagnostic test for male fertility. It measures:

  • Volume of ejaculate (reference: 1.4 mL or above)
  • Sperm concentration (16 million/mL or above)
  • Total sperm count
  • Total motility (percentage of moving sperm)
  • Progressive motility (percentage moving in a forward direction)
  • Morphology (percentage of normal-form sperm)

A single semen analysis can be variable — sperm quality is affected by recent illness, heat, stress, and time since last ejaculation. Most clinics repeat the analysis before drawing firm conclusions.

IVF and ICSI for Male Factor Infertility

Standard IVF involves placing sperm in a dish with an egg and allowing fertilisation to occur naturally — which requires sperm that can navigate to and penetrate the egg. For male factor cases with significantly reduced sperm quality, this process is replaced by ICSI.

Intracytoplasmic sperm injection (ICSI) involves selecting a single sperm under high magnification and injecting it directly into the egg. ICSI bypasses the need for sperm to swim to and penetrate the egg independently. It is now used in the majority of IVF cycles in the UK — both for diagnosed male factor cases and as a standard technique at many clinics.

ICSI does not guarantee fertilisation — the egg still needs to respond — but it removes the sperm motility and penetration barriers from the equation. Fertilisation rates with ICSI are typically 60–75% of injected mature eggs, comparable to or slightly above standard IVF.

Surgical Sperm Retrieval for Azoospermia

For men with azoospermia (no sperm in ejaculate), sperm may be retrieved directly from the testis or epididymis using minor surgical procedures. The main techniques are:

PESA (percutaneous epididymal sperm aspiration). A needle is used to aspirate fluid from the epididymis. Used primarily for obstructive azoospermia. Can often be done under local anaesthetic.

TESA (testicular sperm aspiration). A needle biopsy of the testis. Also used for obstructive cases and sometimes for non-obstructive azoospermia.

TESE (testicular sperm extraction) / micro-TESE. Open biopsy of the testis, with micro-TESE using an operating microscope to identify areas of active sperm production. Used for non-obstructive azoospermia where sperm production is impaired. Sperm found by surgical retrieval are used in ICSI.

Surgical sperm retrieval is typically done on the same day as egg collection or in advance, with sperm frozen for use in the ICSI cycle.

NHS Funding for Male Factor IVF

NHS IVF funding covers couples where male factor infertility is a contributing cause, provided other eligibility criteria are met. Male factor status alone does not automatically qualify a couple for NHS IVF — the ICB's eligibility criteria (which typically cover relationship duration, prior treatment history, age of female partner, and other factors) still apply.

ICSI does not add additional cost complexity under NHS funding — if the couple qualifies for NHS IVF, ICSI is included where clinically indicated.

For patients pursuing private treatment, ICSI typically adds £800–£1,500 to the cost of a standard IVF cycle. Check your current ICB eligibility at nestie.co/nhs.

Lifestyle Factors and Sperm Quality

Sperm quality is substantially more modifiable than egg quality, which is encouraging for men with borderline results.

Heat: The testes are kept approximately 2–4°C below core body temperature for optimal sperm production. Prolonged heat exposure (hot baths, saunas, tight underwear, laptops on the lap) can temporarily reduce sperm quality. Effects are reversible over approximately 3 months (the sperm production cycle).

Smoking: Associated with reduced sperm count, motility, and DNA fragmentation. Stopping smoking is one of the most impactful single changes a man can make to improve sperm quality.

Alcohol: Heavy alcohol consumption is associated with reduced testosterone and sperm quality. Moderate reduction is generally recommended during fertility treatment.

BMI: Both low and high BMI are associated with reduced sperm quality. Obesity in particular is associated with increased sperm DNA fragmentation.

Anabolic steroids: Exogenous androgens profoundly suppress sperm production and can cause azoospermia. Recovery after stopping can take 12–24 months, and in some cases sperm production does not fully recover.

Sperm DNA Fragmentation

Sperm DNA fragmentation (SDF) testing measures the proportion of sperm with damaged DNA. High SDF rates (above approximately 25–30% on some testing platforms) are associated with reduced fertilisation rates, poorer embryo quality, and increased miscarriage risk, even when standard semen parameters are normal.

SDF testing is not part of the routine semen analysis and is not universally offered on the NHS. It is offered privately by some clinics and specialist labs, typically costing £200–£400. Whether testing changes clinical management depends on the result — some clinics offer antioxidant supplementation or modified sperm preparation protocols where high SDF is found.

Frequently Asked Questions

Q: Does my partner's sperm count mean we need ICSI?

A: Not necessarily. For mildly reduced sperm counts with normal motility, standard IVF may be sufficient. ICSI is typically recommended for severe oligozoospermia, poor motility, high SDF, previous poor fertilisation with standard IVF, or use of surgically retrieved sperm. Your clinic's embryologist will advise based on the current semen analysis.

Q: Can supplements improve sperm quality?

A: Some evidence supports antioxidant supplementation (vitamin C, vitamin E, CoQ10, zinc, selenium) for reducing oxidative damage to sperm. However, the evidence base is limited and effect sizes are modest. If sperm quality is borderline, a 3-month course of antioxidants before a treatment cycle is low-risk and may be beneficial, but should not replace treatment if treatment is indicated.

Q: My semen analysis was normal — why are we still having trouble conceiving?

A: Standard semen analysis does not capture all aspects of sperm function. Sperm DNA fragmentation, antisperm antibodies, and the ability of sperm to penetrate an egg are not captured by routine testing. Additionally, female factor or unexplained infertility may be the primary issue. A thorough workup of both partners is warranted.

Q: Does ICSI carry any risks compared with standard IVF?

A: ICSI involves physically injecting a single sperm into the egg, which carries a very small risk of egg damage. Overall ICSI outcomes are comparable to standard IVF. Studies on the health of children born through ICSI have not shown significant differences from IVF-conceived children. Where a genetic cause of male infertility exists (e.g., Y chromosome microdeletion), there is a risk of passing the same condition to male children born through ICSI — genetic counselling is recommended in these cases.

Q: What happens if surgical sperm retrieval finds no sperm?

A: In some cases of non-obstructive azoospermia, TESE or micro-TESE finds no sperm, or insufficient sperm for treatment. This outcome depends on the cause of the azoospermia and cannot always be predicted in advance. Where surgical retrieval fails, the options include donor sperm for IVF/ICSI, or adoption. Your clinic and a specialist urologist can advise on the likelihood of finding sperm based on your specific situation.

This article is for information only and does not constitute medical advice. Discuss your specific situation with a fertility specialist.