Redefining abnormal follicle-stimulating hormone in the male infertility population

Study Type – Diagnostic (validating cohort) Level of Evidence 2a What's known on the subject? and What does the study add? FSH is a hormone released by the anterior pituitary gland via stimulation from gonadotrophin‐releasing hormone and potentially other factors. FSH reflects the status of spermatogenesis (i.e. the ability to produce sperm) as a result of the feedback between the testis and hypothalamus/pituitary glands. An elevated FSH level is indicative of abnormal spermatogenesis and may indicate primary testicular failure. The range for ‘normal’ FSH varies somewhat between institutions but has been defined by the Strong Memorial Hospital (Rochester, NY, USA) clinical laboratory as 1.4–18.1 IU/L based on the ADVIA Centaur (Siemens Medical Solutions, Tarrytown, NY, USA) FSH assay. The findings obtained in the present study could be helpful for predicting male factor infertility in patients with a borderline high FSH level (≈4.5 IU/L) and a low testosterone level compared to someone with a borderline high FSH level and a normal testosterone level. Although the ‘normal’ range for FSH is qualified as a value in the range 1.4–18.1 IU/L, the present study shows that an FSH level >4.5 IU/L was associated with abnormal semen analysis in terms of morphology and sperm concentration in the present patient population. Therefore, these findings suggest that FSH values lower than those currently considered normal may be associated with abnormal semen analysis, and that the ‘normal’ range for FSH used in clinical settings may need to be reconsidered.

OBJECTIVE

• ? To examine the correlation between follicle‐stimulating hormone (FSH) and testosterone/FSH levels with semen analysis parameters to evaluate whether the range for judging normal FSH levels should be reconsidered.

PATIENTS AND METHODS

• ? The present study included 610 male infertility patients from a single urology infertility clinic between 2004 and 2008.
• ? Patients (n = 153) were excluded for obstructive azoospermia, hypogonadotrophic hypogonadism, steroid use or failure to complete testing.
• ? Abnormal semen analysis values were based on the WHO 1999 criteria.
• ? We performed t‐tests, anova , chi‐squared tests and logistic regression to statistically examine the association between the FSH (or testosterone/FSH ratio) level and semen parameters.

RESULTS

• ? The FSH level showed statistically significant associations, as well as evidence of a dose response, with abnormal sperm concentration and morphology but not with semen volume.
• ? In men with FSH levels >7.5 IU/L, the risk of abnormal semen quality was five‐ to thirteen‐fold higher than that of men with FSH levels <2.8 IU/L depending on the specific semen parameter.
• ? Similarly, semen parameters were had a greater probability of being abnormal with decreasing testosterone/FSH ratios.

CONCLUSION

• ? A significantly increased risk of abnormal semen analyses among men with FSH levels >4.5 IU/L and decreasing testosterone/FSH ratios suggests that redefining normal FSH in infertile men would be valuable.