Normal Sperm Count with FSH < 12
Yes, a normal sperm count can absolutely be present with a Follicle-Stimulating Hormone (FSH) level below 12 IU/L, as FSH levels do not definitively predict spermatogenesis status in all cases.
Relationship Between FSH and Sperm Count
FSH is generally negatively correlated with spermatogenesis, meaning higher FSH levels often indicate impaired sperm production. However, this relationship is not absolute:
- Normal FSH reference ranges typically fall between 1.5-8 mIU/mL 1
- FSH levels below 12 IU/L are well within or slightly above the normal range, making normal sperm counts entirely possible
- Men with FSH levels < 12 IU/L often have normal spermatogenesis 2, 1
Evidence Supporting Normal Sperm Count with FSH < 12
Research demonstrates that the relationship between FSH and sperm count is complex:
- The European Association of Urology guidelines (2025) state that FSH levels do not accurately predict the presence of spermatogenesis in all cases 2
- Men with maturation arrest on testicular histology can have normal FSH levels despite having severe spermatogenic dysfunction 2, 1
- A 2012 study suggested that FSH values >4.5 IU/L may be associated with abnormal semen parameters, but this doesn't preclude normal sperm counts at FSH levels between 4.5-12 IU/L 3
- A 1981 study demonstrated that spermatogenesis could be maintained at normal levels even with undetectable blood FSH levels 4
Clinical Implications
When evaluating male fertility with FSH < 12:
- A complete semen analysis remains the gold standard for assessing male fertility regardless of FSH level
- Normal sperm parameters according to WHO criteria can occur across a wide range of FSH values
- Other hormonal parameters should be evaluated alongside FSH, particularly:
- Testosterone levels
- Testosterone/FSH ratio (which may be more predictive than FSH alone) 3
- LH levels
Important Caveats
- While normal sperm counts can occur with FSH < 12, some men with FSH in the upper normal range (4.5-8 IU/L) may still have impaired spermatogenesis 3
- The testosterone/FSH ratio may provide additional insight, with lower ratios associated with higher risk of abnormal semen parameters 3
- FSH levels should be interpreted in the context of other clinical findings, including testicular volume and other hormonal parameters
In conclusion, an FSH level below 12 IU/L is compatible with normal sperm count and fertility in many men, though individual variation exists. The relationship between FSH and spermatogenesis is not strictly linear, and normal sperm counts can be found across a wide range of FSH values.