The biggest concern of parents for precocious puberty is that it affects the height of their children and they are eager to treat it. In the previous article “Can you still grow taller if you have precocious puberty?” we have discussed that not all cases of precocious puberty need to be treated. Not all of them need to be treated with “injections” either. However, if the child has idiopathic central precocious puberty (true precocious puberty, no cause can be found) or secondary central precocious puberty (peripheral precocious puberty turns into central precocious puberty, the primary disease has been treated, the bone age is significantly advanced, the growth potential has been lost, and the predicted lifetime height is not ideal, the pediatric endocrinologist will recommend giving the child an injection for treatment. I. What kind of injection is given? This “injection” refers to the injection of gonadotropin-releasing hormone analog (GnRHa), which is currently the main treatment option for idiopathic central precocious puberty. ”It is an analogue of GnRH secreted in our body, which can compete with natural GnRH for the receptor. gnRHa binds more firmly to the receptor and is not easily degraded; GnRH secreted by the hypothalamus will not work, and the promotion of the pituitary and gonads will not be available. In other words, after this injection, the gonadal axis will be inhibited. The original rapid progression of bone age is inhibited after the injection; that height can continue to grow, prolonging the time to grow taller and slowly improving the final height.” Professor Liang Li said. For girls, the shot can also delay the appearance of the first menstrual period, and for those who already have early menarche, it can temporarily terminate menstruation. For many girls, breast development is a harbinger of accelerated growth, while the onset of menstruation means the beginning of growth deceleration. GnRHa generic names are “Leupro-lide”, “Triptor-elin”, Goserelin and Histrelin. Histrelin), etc. Professor Liang Li told reporters that the two main types of drugs currently used in China are “leuprolide” and “treprostinil”. ”GnRHa is packed in a microcapsule to make a slow-release agent, which can be slowly released in the body after injection. At present, most domestic use 1 month dosage form, playing once, the drug can continue to release 28 to 32 days. That is, this kind of injection, every 28 days to play 1 time.” Liang Li reminded that if it is to improve the height, at least 2 years in a row to play. But this is only the most basic. How long to play, but also take into account to prevent the sexual development remains early after stopping the injection. ”Because at least to continue to play 2 years, if this child began to play at the age of 8 years old, playing to 10 years old, that is not a big problem, you can stop the needle; because this age began to sexual development is also normal. But some girls 5 years old more than 6 years old menstruation, this time to start playing, 2 years later at most only 8 years old; this time to stop the injection, was inhibited by the gonadal axis to restart, sexual development up again, about half a year may be menstruation again.” Professor Liang Li suggests that if the child starts the injection at a very young age, the treatment should be delayed until at least 9 or 9 and a half years old, which means that the duration of the injection should be longer than 2 years to ensure that sexual development does not advance. The youngest child she has come in contact with started getting shots at age 3. “He had a malformation tumor in his skull, a benign growth that did not require surgery. But at just over 3 years old, he already had enlarged penis and testicles, a change in voice, and a very pronounced advance in bone age, so he was given the shot right away. That would definitely require 5 or even 6 years of continuous injections. Because as soon as the injection is stopped, sexual development will start again.” Third, then wait until the child is older before starting the injections, can’t you? This is what Professor Liang Li wants to remind parents that if it is indeed necessary to have the injection treatment, the age to start the injection should be as young as possible. “If the age of girls and boys are over 9 and 10 years old respectively, the bone age has advanced to 11 and 13 years old respectively, and only then start the injection, the effect of improving height will not be obvious, because there is not much room for height growth and the potential is very small.”