Diagnosis of Male Infertility - Hormone Assessment

An evaluation of the pituitary-gonadal axis can provide valuable information on the state of sperm production. In turn, it can reveal problems with the pituitary axis that can cause infertility (hyperprolactinemia, gonadotropin deficiency, congenital adrenal hyperplasia). It is recommended that FSH and testosterone levels be measured in infertile men with sperm densities of < 10 × 106 sperm/mL. Testosterone is a measure of overall endocrine balance. FSH reflects more on the state of sperm production rather than endocrine balance. This combination of tests will detect virtually all (99%) endocrine abnormalities (Sigman and Jarow, 1997). Serum LH and prolactin levels may be obtained if testosterone and FSH are abnormal, to help pinpoint the endocrine defect. Thyroid hormone, liver function, and other organ-specific tests should be obtained if there is clinical evidence of active disease, as uncontrolled systemic illnesses can affect sperm production. The common patterns of hormonal disorders observed in infertility are given in

Table 42-8.

With relatively normal spermatogenesis, low levels of plasma LH and FSH have no clinical meaning; likewise, an isolated low LH with normal testosterone is not significant. The measurement of plasma estradiol should be reserved for those men who appear underandrogenized or have gynecomastia in association with low, normal, or elevated testosterone levels.

A large retrospective study on 1035 infertility patients examined the prevalence of endocrine disorders (Sigman and Jarow, 1997). On initial testing, 20% of infertile men had an abnormal hormone level, but only 9.6% of men harbored a true endocrinopathy on repeat testing. If FSH elevations are excluded, the incidence of clinically significant endocrinopathies in infertile men is 1.7%.

In summary, the indications for hormonal evaluation of the infertile male are:

1. Sperm density of < 10 × 106 sperm/mL on semen analysis
2. Evidence of impaired sexual function (impotence, low libido)
3. Findings suggestive of a specific endocrinopathy (eg, thyroid)

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Revision date: June 22, 2011
Last revised: by Janet A. Staessen, MD, PhD