Menstruation is a sign that a girl has entered puberty. Generally, girls menstruate between the ages of 10 and 16, with the average being around 14 years old, but some children menstruate before the age of 10. Menstruation before the development of secondary sexual characteristics belongs to precocious puberty, if at the age of 16 years old has not menstruation, also need to actively carry out tests to rule out primary amenorrhea. The age of menarche is related to genetic factors, the girl’s physical condition, nutritional status, living environment, etc. Menstruation coming too early or too late will affect the growth and development of girls. It is recommended to develop good living habits, eat regularly, sleep regularly, do not stay up late, eat less hormone-containing food, eat more seasonal fruits and vegetables, and pay attention to the hygiene of the menstrual period after menstruation.