Irregular menstruation in 13-year-old girls is a normal phenomenon and does not require interventional treatment. 13-year-old girls have strong hormonal secretion, especially estrogen secretion, when they first start menstruating. Most sexual organs are not yet mature and ovulation is irregular, so menstruation is prone to irregularity. The main manifestations are irregular menstrual cycle length, low menstrual volume, dysmenorrhea, blood clots, etc. As the sexual organs and mammary glands develop and mature with age, most irregular menstruation can be relieved by themselves. Most children have regular periods six months after the first menstruation, and some children may continue to have regular periods until 2-3 years later. During menstruation, a light diet is recommended to avoid cold, greasy, spicy and stimulating foods. Before, during and after the menstrual period, it is important to keep the abdomen warm and avoid getting cold in the abdomen to avoid aggravating the symptoms of irregular menstruation.