LEP and polycystic ovary syndrome: By contrast, in the PCOM–NON-STRESS group, leptin levels were elevated but unrelated to gonadotropic output, consistent with central leptin resistance typically seen in classic PCOS, which is likely mediated by hyperinsulinemia or low-grade inflammation (Lian et al. 2016; Spritzer et al. 2015; Laughlin et al. 1997; Peng et al. 2022 and Zheng et al. 2017).