Clinical Characteristics of Precocious Puberty Girls and Comparison Analysis of GnRH Test Results with Diagnosis Type

Purpose: Precocious Puberty is defined as the development of secondary sexual characteristics in girls younger than 8 years. In this study, we retrospectively analyzed the diagnostic difference of the GnRH (Gonado-tropin-releasing Hormone) stimulation test results with medical records of Precocious puberty in girls.

Methods: 118 girls were enrolled from Seoul National University Bundang Hospital Pediatrics, Endocrinology Internal Medicine due to early onset of sexual development from February 2016 to December 2016. They were divided into 3 groups; True precocious puberty group (n=57), early puberty group (n=39), and premature thelarche (n=22) group. Tanner stage, chronological age, bone age, height, and body weight for each group were collected. GnRH test results including LH (basal, 30min, 45min, 60min), FSH (basal, 30min, 60min) were compared for each group. peak value distribution of LH and FSH, peak LH/basal LH ratio, peak LH/Peak FSH ratio were assessed for each group. P-value 0.05 was used as statistical threshold. Result: For height and weight, there was no significant difference among three groups (P>0.05). However, there was significant differences among three groups in the chronologic age and bone age (P=0.0002, for chronologic age 7.1yrs±0.81 vs 8.05yrs±0.03 vs 7.02yrs±0.58, for bone age 9.9yrs±0.9 vs 10.0yrs±0.62 vs 8.04yrs±1.29 for each group). In precocious puberty group, peak LH level was shown at 30min (82.5%), 45min(12.3%) or 60min(5.3%), and peak FSH level was shown at 30min(8.8%), or 60min(91.2%). In early puberty group, peak LH level was shown at 30min(79.5%), 45min(17.9%), or 60min(2.6%), and peak FSH levels at 30min(7.7%), or 60min(92.32%). In premature thelarche group, peak LH level was shown at 30min(32%), 45min(59%), or 60min(9.0%) and peak FSH levels at 60min(100%). Conclusion: In order to diagnose the true precocious puberty , LH peak after GnRH stimulation is increased by more than two to three times compared to baseline or a predetermined level or more than 5~10 IU/L increases. GnRH stimulation test could be the most accurate method in diagnosis of precocious puberty by evaluating the hypothalamus-pituitary gland-gonad axis.