The following reasons need to be considered for increased menstruation in girls. In normal state, a girl’s menstruation is 50-80mL, when it exceeds 80mL, you generally need to consider the formation of endometrial thickening and endometrial polyps, and the above state may result in heavy menstruation. Then there is submucosal fibroids. For huge fibroids, fibroids can cause an increase in the surface area of the uterine cavity, or a significant increase in menstrual flow along with co-infection. In addition, there is also adenomyosis, in which the menstrual flow may increase significantly and may be combined with dysmenorrhea. In some cases, women with coagulation problems may have a very high menstrual flow, so it is important to consider whether there is a deficiency of coagulation factors or thrombocytopenia, or a malignant lesion. For girls with increased menstrual flow, it is important to go to the hospital as soon as possible to find out the cause of increased menstrual flow and give targeted treatment to prevent severe anemia or even shock.