Tummy pain during menstruation is clinically common due to the following reasons: 1. due to the secretion of a large amount of prostaglandins by the endometrium during shedding, which stimulates the uterus to contract and causes stomach pain. 2. caused by endometriosis, which often results in progressive aggravation of dysmenorrhea and is accompanied by infertility. If the endometriosis lesion is ectopic in the muscle layer of the uterus, it can lead to particularly heavy menstrual flow. If the ectopic site is in the ovary, it will manifest as ovarian chocolate cyst and surgery is recommended.3. For menstrual stomach pain caused by inflammation, gynecological examination after menstruation is clean is recommended to find out whether there is pressure pain in the uterine adnexa, and if there is pressure pain, anti-inflammatory treatment should be actively given.4. Due to malformation of uterine development, it will affect the uterus causing uncoordinated contraction during menstruation, which will lead to stomach pain.