Serum OC levels were significantly higher in CPP group compared with control group (76.8 ± 10.5 vs. 61.6 ± 15.1ng/mL, p=0.001). Serum OC levels were correlated with peak LH levels during GnRH stimulation test (r=0.348, p=0.037), bone age (r=0.403, p=0.010) and bone age advance (r=0.323, p=0.042), but not related to age, height, weight and BMI.