Irregular menstruation is normal for 12 year old girls, because when a 12 year old girl has just come to menstruation, it is the first period of menstruation. 12 year old girls belong to the stage of puberty, the ovaries of puberty are not fully developed to normal, the ovaries still have regular ovulation, so irregular menstruation may occur, the period of menstruation will be prolonged or the amount of menstrual blood, menstruation time is long, all belong to the normal These are normal reactions. After puberty, as the ovaries mature, most women begin to have regular menstruation, i.e., regular periods and normal menstrual flow. Therefore, if a 12-year-old girl has irregular menstruation, she can be observed clinically, and after excluding organic lesions, psychological guidance should be given to avoid anxiety and tension.