Circulating Anti-Müllerian Hormone, Activins, Inhibins, and Follistatin in Women with Polycystic Ovary Syndrome and Idiopathic Hirsutism: A Case–Control Study

Background: Hirsutism is characterized by excessive terminal hair growth in androgen-sensitive areas in women. Idiopathic hirsutism (IH) is the second most common cause after polycystic ovary syndrome (PCOS), yet its pathophysiology remains unclear. Objective: To evaluate serum levels of anti-Müllerian hormone (AMH), activins, inhibins, and follistatin in women with PCOS-related and IH. Methods: This cross-sectional study included 55 hirsute women with PCOS, 50 with IH, and 50 age- and body mass index–matched healthy controls. Menstrual patterns and modified Ferriman–Gallwey scores were recorded. Serum levels of AMH, activin A, activin B, inhibin A, inhibin B, follistatin, and relevant reproductive hormones were measured. Results: AMH levels were significantly higher in patients with PCOS compared with the IH and control groups ( P < 0.001 and P < 0.05, respectively), whereas no significant difference was observed between the IH and control groups. Activin B levels did not differ among groups; however, activin A levels were lower in the PCOS group than in controls ( P < 0.05). In contrast, inhibin A, inhibin B, and follistatin levels were significantly higher in the PCOS group compared with controls ( P < 0.01, P < 0.05, and P < 0.05, respectively). Inhibin A and inhibin B levels were also higher in the IH group than in controls. No significant differences in activins, inhibins, or follistatin were found between PCOS and IH groups. In multivariate analysis, only AMH remained independently associated with PCOS and showed a moderate ability to distinguish PCOS from non-PCOS subjects (area under the curve = 0.677). Conclusion: Women with PCOS exhibited altered serum levels of AMH, inhibins, follistatin, and activin A compared with controls. AMH levels were higher in PCOS than in IH, whereas inhibin A and inhibin B levels were elevated in both PCOS and IH. These findings suggest that these hormones are associated with the endocrine profile of PCOS and IH and may contribute to the characterization of hyperandrogenic conditions.