Diagnostic work-up of 449 consecutive girls who were referred to be evaluated for precocious puberty.

OBJECTIVE: A decrease in age at pubertal onset has been observed internationally. The aim of this study was to describe a large cohort of Caucasian girls referred with signs of early puberty according to etiology and compare biochemical characteristics.

METHODS: In this single-center study, we included 449 consecutive Caucasian girls who were referred with signs of early puberty during the years 1993-2009. We evaluated pubertal stage, height, weight, and bone age. FSH, LH, estradiol, and inhibin B were determined, and a standard GnRH test was performed. Brain magnetic resonance imaging was performed to rule out pathologies.

RESULTS: During the period from 1993-2008, we found an increase in the number of girls in most diagnostic groups. Of 449 girls, 88 had central precocious puberty (CPP), and 12 of these had an organic origin. A total of 129 had early-normal variant (8-9 yr), 69 had premature thelarche, and 49 premature adrenarche. Receiver operating characteristic analyses revealed that basal LH was superior in predicting the maximal LH level during GnRH testing in comparison with FSH, estradiol, and inhibin B levels. Basal LH levels were above the age-related 2 sd in 26.2, 19.6, 65.1, and 75.0% of girls with, respectively, early-normal variant, premature thelarche, idiopathic CPP, and organic CPP, but LH levels below the detection limit were also seen among girls with a pubertal GnRH test.

CONCLUSION: We observed an increasing number of girls referred because of early pubertal signs. An elevated basal LH was highly predictive of a pubertal GnRH test result, whereas a low LH did not exclude central pubertal activation.