Anti-Müllerian Hormone and Ovarian Morphology in Polycystic Ovary Syndrome (PCOS)/Polyendocrine Metabolic Ovarian Syndrome (PMOS): Toward More Precise Diagnosis and Phenotype Stratification

Abstract

Polycystic ovary syndrome (PCOS), recently proposed to be reframed as polyendocrine metabolic ovarian syndrome (PMOS), remains diagnostically challenging because its clinical expression extends beyond ovarian morphology to androgenic, ovulatory, metabolic, and life-stage-dependent domains. This review critically examines anti-Müllerian hormone (AMH) and ovarian morphology as complementary, but non-interchangeable, markers of the ovarian component of PCOS/PMOS. AMH reflects granulosa-cell activity within the pre-antral and small-antral follicle pool and is frequently elevated in PCOS due to increased follicle number and enhanced AMH production per follicle. Ultrasound-defined polycystic ovarian morphology, in contrast, provides anatomical evidence of small-follicle excess, ovarian volume, and structural context, but remains sensitive to imaging technology, operator expertise, follicle-counting thresholds, and reproductive stage. The 2023 International Evidence-Based Guideline permits AMH as an alternative to ultrasound for defining polycystic ovarian morphology in adults, but not as a stand-alone diagnostic test and not for adolescent diagnosis. This distinction is central, as AMH and ovarian morphology primarily define the ovarian follicle-burden domain and should not be used to infer androgenic severity, insulin resistance, cardiometabolic risk, or whole-syndrome burden. The emerging PMOS concept strengthens this interpretation by shifting emphasis away from the misleading ‘cystic’ terminology toward a multidomain endocrine–metabolic–ovarian framework. Precision diagnosis should therefore integrate AMH or ovarian morphology with hyperandrogenism, ovulatory dysfunction, metabolic assessment, age, BMI, ethnicity, assay platform, and reproductive stage to support phenotype stratification and clinically meaningful decision-making.