C3 and polycystic ovary syndrome: The levels of alternative pathway complement activation component C3 were higher in both obese PCOS (p = 0.04, obese PCOS vs. control) and nonobese PCOS (p = 0.002, non-obese PCOS vs. control); however, the functional fragment of C3 cleavage, C3a, was only elevated in nonobese PCOS compared to controls (p = 0.007), together with the elevation of its product C3desArg (p = 0.004), but was no different in obese PCOS.