What is the relationship between polycystic ovary syndrome (PCOS) and hirsutism?

Updated: May 01, 2020
  • Author: George T Griffing, MD; Chief Editor: Michel E Rivlin, MD  more...
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PCOS is the most common ovarian disorder associated with hirsutism. Although the cause of PCOS is not known, the etiology is speculated to be multifactorial. By definition, polycystic ovaries have 20 or more subcapsular follicles, which range from approximately 1-15 mm in diameter. The follicles are at various states of atresia, and hyperplasia of the theca interna, the anatomic source of ovarian androgens, is present. However, the basic abnormalities in PCOS are functional, rather than anatomic, in nature. In particular, levels of luteinizing hormone (LH) are tonically elevated (with LH levels higher than those of follicle-stimulating hormone [FSH]).

Many women with PCOS have insulin resistance, manifested by acanthosis nigricans and elevated plasma insulin levels. Increased insulin levels have been speculated to stimulate androgen production from the ovarian theca interna cells. An experiment in nature supports this hypothesis; women with PCOS who have a specific genetic mutation that lowers insulin resistance have lower hirsutism scores. In addition, the importance of insulin resistance is emphasized by the therapeutic effect of insulin-sensitizing medications (eg, metformin, thiazolidinediones), which restore normal ovarian androgen production and ovulation. [12]

PCOS usually begins at puberty. The incidence has been estimated to be approximately 5% among adolescent girls and adult women in the United States. As noted, the characteristic endocrine abnormality is an elevation in levels of plasma free testosterone that is not suppressed by dexamethasone; however, as many as 50% of patients also show abnormal adrenal androgen secretion.

A study by Villarroel et al indicated that in adolescent girls, hirsutism and oligomenorrhea (persistent menstrual cycles >45 days) have a strong association with the presence of biochemical hyperandrogenism and polycystic ovarian morphology and are therefore useful in the diagnosis of PCOS. [13]

A study by Turan et al indicated that in patients with PCOS, hyperandrogenism contributes to the elevation of hearing thresholds. Among the study’s subjects, the investigators found that increased free testosterone index values and hirsutism scores were associated with a greater extended high-frequency threshold. [14]

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