In both lean and obese women with PCOS, follicular fluid is characterized by unchanged [157] or lower levels of E2 [126,158,159] and lower levels of progesterone (P4) [157,158,160,161] and melatonin [158], while the levels of testosterone (T) [157,158,159,160,161] and AMH [162] are markedly increased. Here, AMH is linked to polycystic ovary syndrome.