A report from the April 2023 journal: Urology by Fantus et al (Urology department, Northwestern) reports on findings of semen analysis over time on patients with normal baseline FSH and sperm density compared to their cohorts with elevated FSH who also had normal sperm density and changes over time in their semen analysis.
Commonly used hormonal blood tests in the assessment of male fertility include the pituitary hormones FSH (follicle stimulating hormone) and LH (luteinizing hormone) as well as the testicular hormone testosterone.
Normal FSH is measured at a value of less than 7.6 IU/ml. It is well known that markedly elevated FSH higher than 20 IU/ml) is often associated with non-obstructive azoospermia (no sperm in the ejaculate due to poor or absent sperm production) where as Normal FSH is associated with normal levels of sperm production.
In this study, results of semen analyses from a total of 858 men, 776 with a normal FSH and 82 with an elevated FSH were followed over time. At baseline, Men with elevated FSH had lower total motile sperm count. and at each follow up in time, the elevated FSH group were more likely to develop oligospermia (low perm count) and a decline in total motile sperm count to levels that would make IUI (intra uterine insemination) less likely to succeed.
There are several takeaways from this paper. The first is that semen analysis is a less than perfect tool for the assessment of fertility over time. The second calls into question whether serum FSH should be measured at initial evaluation regardless of a normal semen analysis as it may lead to counseling for further evaluation into the future. As the paper points out, AUA guidelines do not require hormonal evaluation in the setting of a normal semen analysis. Finally, the concept of what the authors refer to as “compensated hyposermatogenesis” is compelling and begs the question as to whether there are any other serum markers that may be appropriate to look at in this regard.
In my own practice, I must confess that I do not routinely look at serum hormone levels in the face of normal, robust, semen analysis results. I may need to reconsider.