The clinical manifestations of hyperprolactinemia are relatively few and usually easy to recognize. Once the presence of prolactin excess is identified, further evaluation to establish the underlying cause is usually straightforward. The clinical manifestations and diagnosis of hyperprolactinemia are reviewed here. The causes and treatment of hyperprolactinemia are discussed elsewhere. (See "Causes of hyperprolactinemia" and "Treatment of hyperprolactinemia due to lactotroph adenoma and other causes".)
Hyperprolactinemia causes typical symptoms in premenopausal women and in men, but not in postmenopausal women.
Premenopausal women — Hyperprolactinemia in premenopausal women causes hypogonadism, manifested by infertility, oligomenorrhea, or amenorrhea [1,2], and less often by galactorrhea.
Hypogonadism — Excluding pregnancy, hyperprolactinemia accounts for approximately 10 to 20 percent of cases of amenorrhea. The mechanism appears to involve inhibition of luteinizing hormone (LH), and perhaps follicle-stimulating hormone (FSH) secretion, via inhibition of the release of gonadotropin-releasing hormone (GnRH). As a result, serum gonadotropin concentrations are not supranormal, typical of other causes of secondary hypogonadism.
The symptoms of hypogonadism due to hyperprolactinemia in premenopausal women correlate with the magnitude of the hyperprolactinemia. In most laboratories, a serum prolactin concentration above 15 to 20 ng/mL (15 to 20 mcg/L SI units) is considered abnormally high in women of reproductive age.