Reassessing the Luteinizing Hormone/Follicle‐Stimulating Hormone Ratio in Polycystic Ovary Syndrome: Associations With a Possible Neuroendocrine and Anti‐Müllerian Hormone‐Related Phenotype

PURPOSE: To comprehensively reassess the clinical and metabolic significance of the luteinizing hormone (LH) to follicle-stimulating hormone (FSH) ratio in women with polycystic ovary syndrome (PCOS), and to investigate whether it is associated with a clinical and hormonal pattern consistent with a possible neuroendocrine-dominant subgroup, distinguishable from insulin-related metabolic presentation. DESIGN: Observational cross-sectional study. METHODS: This retrospective cross-sectional study included 316 women diagnosed with PCOS according to the Rotterdam criteria at a tertiary university hospital. Patients were categorised based on their LH:FSH ratio (using a cut-off of 2) and their PCOS phenotypes (Phenotypes A, B, C, and D). Clinical, hormonal, and metabolic parameters, including anti-Müllerian hormone (AMH) levels and ovarian volume, were compared across groups. RESULTS: Among 316 patients, 18.35% had an LH:FSH ratio >2. A strong positive correlation was found between LH:FSH ratio and AMH levels (r = 0.65, p < 0.001), and a significant correlation was observed with ovarian volume (r = 0.20, p = 0.001) and polycystic ovarian morphology (mean LH:FSH 1.59 vs. 1.15, p < 0.001). Patients with phenotype D (OA + PCOM, non-hyperandrogenic PCOS) exhibited the highest LH:FSH ratio (1.75 ± 0.87). Higher LH:FSH ratios were associated with oligo/amenorrhea (1.59 vs. 1.22, p < 0.001), anovulation (1.66 vs. 1.16, p < 0.001), and lower midluteal progesterone (ρ = -0.28, p < 0.001), but not with serum androgens or Ferriman-Gallwey scores. Weak positive correlations were observed with insulin levels (ρ = 0.18, p = 0.022) and HOMA-IR (ρ = 0.18, p = 0.021), but no significant associations were found with BMI, glucose tolerance, or lipid profile. CONCLUSION: A high LH:FSH ratio is associated with a clinical and hormonal pattern-including elevated AMH levels, prominent PCOM, and anovulation-that may be consistent with a neuroendocrine-dominant presentation of PCOS, rather than metabolic or androgenic disturbances. If confirmed by prospective studies, this association could inform more individualised therapeutic approaches.