In my daily work, when I come across girls in middle school who are accompanied by their parents to seek medical attention because of irregular menstruation, I am often asked, “Does it matter?”. Teenage girls are confused and their parents are nervous and anxious. Today, I would like to talk about menstrual disorders in adolescents. Menstrual disorders in adolescents can be caused by a variety of factors, including psychological and physical stress, endocrine disorders (e.g., thyroid dysfunction, ovarian dysfunction, etc.), inflammation, medications, bleeding disorders, anemia, and nutritional deficiencies (e.g., weight loss). Adolescence is a stage of transition from the end of childhood to sexual maturity. The onset of menstruation signifies that the hypothalamus-pituitary-ovarian axis of the brain has established a connection, but further development and maturation is needed so that regular menstruation with regular ovulation can be established. In most adolescents, maturation to a more regular menstrual cycle occurs eighteen months after menarche. Most menstruation before this time is not regular ovulation. After menarche, 95% of cycles are greater than 90 days. In the third year after menarche 95% are 21-45 days. So, as a parent, how should you observe your daughter’s menstruation? Normal menstrual cycle average 28 days (24-35 days), menstrual period of 4-6 days, the average bleeding volume of 30ML, to be less than 80ML, the daily estimated menstrual volume should not be more than about 30 sanitary napkins. Abnormal menstruation means: menstrual period greater than 7 days, menstrual cycle less than 21 days or greater than 45 days, menstrual cycle greater than 90 days, bleeding between periods. If the girl has a long period of vaginal bleeding, dizziness, lightheadedness, fatigue, shortness of breath after activity, palpitations, swelling of the lower limbs, poor sleep, etc. may appear anemia. Parents should accompany her to the doctor in time.