OBJECTIVETo study the relationship between the suppression of the hypothalamic-pituitary-gonadal axis (HPGA) and the predicted adult height (PAH) in girls with central precocious puberty (CPP) during the treatment with gonadotropin-releasing hormone analogue (GnRHa), in order to provide guidance for individualized GnRHa dose adjustment in clinical practice.

METHODSThe clinical data of 75 CPP girls were collected, and then height, bone age (BA), uterine and ovarian volumes, and peak luteinizing hormone (LH), peak follicle-stimulating hormone (FSH), and estradiol (E2) levels were recorded at different time points of GnRHa treatment. PAH at each time point was calculated. PAH improvement (ΔPAH=PAH-target height) and its relationship with the degree of HPGA suppression were analyzed. Threshold effect analysis was applied to determine the best HPGA suppression range forΔPAH.

RESULTSAfter GnRHa treatment, PAHs were improved markedly compared with the data in the early stage of treatment. ΔPAH showed a negative correlation with ΔBA. At 24 months of treatment, ΔPAH was also negatively correlated with LH. Uterine volume controlled between 2.3 and 3.0 mL, LH level controlled below 0.8 IU/L, and FSH controlled below 2.4 IU/L could slow down the growth of BA and improve PAH.

CONCLUSIONSGnRHa treatment can improve the PAH of CPP girls. Selection of an appropriate therapeutic dose for GnRHa to control uterine volume, LH and FSH levels within certain ranges can slow down the growth of BA and improve PAH.