Dysmenorrhea may also occur when the menstrual flow is not heavy, because dysmenorrhea has little to do with the amount of menstrual flow, and is mainly related to the following factors:1. When menstruation occurs, the endometrium sheds its lining and secretes a large amount of prostaglandins, and some people are relatively sensitive to this, which can cause the uterus to contract and lead to pain in the lower abdomen.2. Dysmenorrhea may occur in the presence of pelvic inflammation, and in the case of endometriosis, dysmenorrhea may also occur. Dysmenorrhea can also occur in the presence of endometriosis, and dysmenorrhea can also occur in the presence of uterine developmental abnormalities. Once dysmenorrhea occurs, it is important to identify the cause and treat it accordingly. If the total menstrual flow is less than 30mL, it is necessary to do the appropriate examination to understand the cause of low menstrual flow, and then give the appropriate treatment. In daily life, it is best to develop good habits, do not stay up late, will also have a relatively small impact on menstruation.