The effects of gonadotropin releasing hormone anologue on the growth of the girls with idiopathic central precocious puberty

Objective To observe the effect of gonadotropin releasing hormone analogue (GnRH A) on growth and predictive adult height for the girls with idiopathic central precocious puberty (ICPP). Methods 19 girls with ICPP were treated with slow release GnRH A (50～60 μg/kg intramuscularly every 4 weeks). Initial age of treatmant was 8.5±1.1 years old (range 6～11 years), with therapeutic duration 6～31 months. Sexual characteristics, growth velocity and bone age (BA) were observed, and the height standard deviation score (SDS) for BA (HtSDS BA ) and predicted adult height for the target height SDS (PHtSDS THt ) were analysed. Results After treatment, the breasts and the serum oestrogen levels returnted to the prepubertal situation and growth velocity decreased to the prepubertal rate, maturation of BA slowed significantly with a ΔBA/ΔCA ratio of 0.6±0.2attheend of treatment,HtSDS BA increased from -1.45±0.64 to -1.05±0.59 (P0.05) while PHtSDS THt increased from -0.99±0.83 to -0.09±0.90 (P0.01). Increment in predictive adult height correlated positively to the duration of treatment (r=0.82, P0.01). Conclusion GnRH A can effectively depress the development of sexual characteristics, reduce the difference among height age bone age chronologic age, and improve the predictive adult height in girls with ICPP by retarding maturation of BA effectively when an adequate course of therapy is performed.