I. Treatment goals of precocious puberty Precocious puberty can be divided into two categories: central precocious puberty (also known as true precocious puberty or GnRH-dependent precocious puberty, CPP) and peripheral precocious puberty (also known as pseudoprecocious puberty or non-GnRH-dependent precocious puberty, PPP). CPP mainly includes idiopathic precocious puberty (ICPP) and precocious puberty due to central nervous system diseases (e.g., viral encephalitis, meningitis, or organic lesions such as tumors of the hypothalamus, pituitary gland, or pineal gland). 80%-90% of female children with CPP have ICPP, while 80% of male children have ICPP. The etiology of PPP is mainly due to gonadal and adrenal diseases, which are caused by excessive secretion of gonadal hormones. The main risks of ICPP are: (1) premature development brings serious social and psychological burdens to children who are not yet mature; (2) early onset of development and lower base height than those with normal development; early exposure of female children to excessive estrogen levels leads to accelerated aging of the growth plate and early epiphyseal closure, resulting in lower adult height (adult height). In female children, early exposure to excessive estrogen levels leads to accelerated aging of the growth plate, resulting in early epiphyseal closure and lower adult height. Therefore, the objectives of ICPP treatment include: (1) to stop the premature development of sexual organs until the age of normal puberty onset, and to prevent the development of secondary sexual characteristics that have already appeared; (2) to inhibit the rate of skeletal maturation in order to achieve normal or near-normal adult height; and (3) to prevent the psychological problems associated with premature maturation and early menarche. The core of the program is to improve the adult height of the patient. PPP and non-specific CPP are mainly caused by the primary cause, such as headache, nausea, vomiting and other symptoms of increased cranial pressure due to tumor or local compression, such as compression of the optic nerve causing visual impairment and visual field defects. The goal of treatment is to remove the cause of the disease, improve the state of precocious puberty and maintain the endocrine function of normal development of children. 4. What kind of precocious puberty does not need treatment For PPP and non-specific issue CPP, treatment is needed for the primary cause, but not all ICPP needs treatment. According to the 2010 Ministry of Health Guidelines for the Treatment of Precocious Puberty (for trial implementation), ICPP generally does not require treatment in the following cases: (1) those with slow sexual maturation (orphan progression not exceeding age progression) and no significant impact on adult height; (2) those with advanced bone age (BA) but with rapid height growth rate and no impaired predicted adult height. (2) Those who have advanced BA but have rapid growth rate and no impairment of adult height. In addition, pubertal development is a dynamic process, so for those who do not need treatment for the time being, regular review and evaluation are needed to adjust the treatment plan. V. Problems in the treatment of GnRHa GnRHa has been used in the treatment of CPP for more than 20 years and is the standard therapeutic drug for the treatment of CPP. The principle of its treatment is that the physiological effects of GnRH have a dual nature of measurement, with excitatory effects on pituitary gonadotropins when injected in small pulses and inhibitory effects when injected in large consecutive doses. Therefore, generally GnRHa injection can cause temporary increase of GnRH, testosterone and estradiol levels within a few days, and gradually decrease to pre-pubertal level after 1 week, gradually until the sex hormones are completely suppressed, and the secondary sex characteristics change, the girls’ mammary glands shrink, pubic hair decreases and menstruation decreases, and the boys’ testicles shrink, pubic hair decreases and penile erection decreases. The growth rate can be reduced to 5-6cm/year after 6 months of treatment, thus delaying the growth and fusion of epiphysis to achieve the purpose of prolonging the growth years and improving the adult height. VI. Indications for the treatment of GnRHa The specific recommendations of the 2010 Ministry of Health Guidelines for the Treatment of Precocious Puberty (for trial implementation) are as follows: (1) Bone age – actual age ≥ 2 years; and girls ≤ 11.5 years and boys ≤ 12.5 years are required. (2) Predicted adult height: <150cm for girls and <160cm for boys. (3) Or a height standard deviation Z-score SDS <-2SD judged by bone age (judged by normal population reference values or genetic target height). (4) Rapid developmental progression with bone age growth/CA growth > 1.