The occurrence of dysmenorrhea is related to the following factors: First, psychosomatic factors. In primary dysmenorrhea, mental factors are more important factors. Adolescent girls have immature development of reproductive organs, no correct understanding of menstruation, and not enough mental and emotional stability. Severe cases will think anxiety and depression, all of which will lead to plant nerve dysfunction and make the uterus contract too strongly, thus causing dysmenorrhea. Second, the uterus factor. The development of the uterus of young girls is not perfect, such as uterine dysplasia, cervical canal stenosis, abnormal position of the uterus, etc., will lead to poor flow of menstrual blood, causing dysmenorrhea. Thirdly, the factor of endocrine. Increased prostaglandin content in the endometrium and menstrual blood can cause spasmodic contraction of the smooth muscle of the uterus, resulting in ischemia of the uterus causing dysmenorrhea. Fourth, physical factors. Some girls usually do not have dysmenorrhea, but will have dysmenorrhea when there are problems with their health, such as patients with anemia or other chronic diseases, often accompanied by dysmenorrhea. In addition, feeling cold, wading in the rain or being exposed to humidity during menstruation may lead to dysmenorrhea.