Abdominal pain during menstruation, clinically known as dysmenorrhea, causes dysmenorrhea for the following reasons: First, in the time of menstruation is bleeding caused by the shedding of the endometrium, when the endometrium is shed, a certain amount of prostaglandins will be released, due to different individual differences, the degree of sensitivity to prostaglandins is not the same, someone relatively sensitive case, it will cause contraction of the smooth muscle of the uterus, and The second reason is that the pelvis has chronic pain. Second, because of chronic inflammation in the pelvis, when the pelvis itself is inflamed, there will be congestion and edema, and menstruation will make the congestion and edema worse, so there will be dysmenorrhea. Third, because of endometriosis in the menstruation, the ectopic lesion will also appear bleeding symptoms, so it will lead to pain in the lower abdomen, for dysmenorrhea to find out the cause before giving better treatment, to achieve the purpose of cure.