In a man with testicular atrophy, is a decrease in semen concentration from 56 million/mL to 43 million/mL over six weeks a typical finding?

Testicular Atrophy and Sperm Count Decline: Expected Patterns

A decrease from 56 million/mL to 43 million/mL over six weeks is NOT the typical pattern expected with testicular atrophy—this modest decline falls well within normal biological variability and does not reflect the severe spermatogenic impairment characteristic of true testicular atrophy. 1

Understanding Normal Sperm Count Variability

Biological variation between semen samples is expected and substantial, even in men with normal fertility:

• Within-subject variation for total sperm count ranges from 42% to 75% coefficient of variation, meaning your observed decline from 56 to 43 million/mL (a 23% decrease) falls entirely within normal fluctuations 2
• The WHO strongly recommends obtaining at least two semen analyses separated by 2-3 months before drawing any clinical conclusions, as factors such as abstinence duration, hydration status, recent illness, stress, and minor laboratory handling differences can influence results 1
• This variation can be reduced to 12% by averaging counts from multiple samples, but single comparisons remain highly unreliable 2

Both your values (56 and 43 million/mL) exceed the WHO lower reference limit of 16 million/mL by substantial margins, placing you well within the normal fertile range at both time points 3, 1

What True Testicular Atrophy Actually Causes

If you genuinely have testicular atrophy, the expected spermatogenic pattern is dramatically different from what you're experiencing:

Severe Oligospermia or Azoospermia Pattern

• Men with testicular atrophy typically present with sperm concentrations <5 million/mL when accompanied by elevated FSH and reduced testicular volume 3
• Non-obstructive azoospermia (complete absence of sperm) is the classic presentation of severe testicular atrophy, characterized by testicular volumes <12 mL, elevated FSH >7.6 IU/L, and complete or near-complete absence of spermatogenesis 4
• The principal spermatogenic lesion in testicular dysfunction is marked (90%) inhibition of type A→B spermatogonial maturation, leading to profound reductions in all downstream germ cell populations 5

Hormonal Markers of Testicular Atrophy

• FSH levels >7.6 IU/L strongly suggest non-obstructive azoospermia when accompanied by testicular atrophy and absent or severely reduced sperm production 3, 4
• Testicular atrophy with preserved spermatogenesis (as you appear to have) suggests your testicular reserve may be reduced but not yet causing severe impairment 4

Critical Distinction: Testicular Size vs. Function

Testicular volume does not perfectly predict sperm production:

• Even men with severe testicular atrophy (volume ≤2 mL) achieve 55-56% sperm retrieval rates with microsurgical testicular sperm extraction, demonstrating that focal areas of spermatogenesis can persist despite marked atrophy 6
• Bilateral testicular hypotrophy (both testes <14 mL) is nearly 9 times more likely to cause total motile sperm count <20 million compared to men without hypotrophy, but unilateral hypotrophy alone does not predict impaired semen quality 7
• Your sperm concentrations of 43-56 million/mL suggest preserved spermatogenic function despite any anatomical atrophy 1

What You Should Actually Monitor

Essential Next Steps

• Obtain at least one more semen analysis 2-3 months from now to establish whether your parameters are stable, declining, or improving—single comparisons are meaningless given 42-75% natural variability 1, 2
• Measure FSH, LH, and total testosterone to determine if you have primary testicular dysfunction (elevated FSH/LH with low-normal testosterone) versus normal hormonal function 4
• Physical examination by a urologist to assess testicular volume using Prader orchidometer, check for varicocele, and evaluate testicular consistency 8

Red Flags Requiring Urgent Evaluation

• Sperm concentration dropping below 5 million/mL warrants karyotype analysis and Y-chromosome microdeletion testing 3
• Progressive decline over serial analyses (not just two data points) suggests active testicular injury requiring investigation 1
• Rapid testicular atrophy or development of palpable testicular mass requires immediate urology referral 8

Protective Actions to Preserve Fertility

• Never use exogenous testosterone or anabolic steroids—these completely suppress spermatogenesis through negative feedback, causing azoospermia that can take months to years to recover 4
• Consider sperm cryopreservation (banking 2-3 ejaculates) if you have documented testicular atrophy with volumes <12 mL, as this represents reduced testicular reserve with risk of future decline 4
• Optimize modifiable factors: smoking cessation, maintain healthy body weight (BMI <25), minimize heat exposure to testes, and avoid gonadotoxic medications 4

Bottom Line

Your observed decline from 56 to 43 million/mL is entirely consistent with normal biological variability and does NOT represent the severe spermatogenic impairment expected with true testicular atrophy. If you genuinely have testicular atrophy, you would typically see sperm concentrations <5 million/mL or complete azoospermia, not values 2.5-3.5 times above the normal reference limit. Obtain repeat semen analysis in 2-3 months and hormonal evaluation (FSH, LH, testosterone) to establish your true baseline and determine if testicular dysfunction is actually present. 1, 4