Pain in the middle of the abdomen is considered to be pelvic inflammatory disease, cervicitis, endometriosis and so on. 1. Pelvic inflammatory disease: Pelvic inflammatory disease is an infectious disease of the upper reproductive tract of women, due to inflammatory stimulation will have the symptom of lower abdominal pain, usually persistent pain, symptoms will be aggravated after sexual intercourse or activities. 2. Cervicitis: Cervicitis is an inflammation of the cervical-vaginal part of the uterine cervix and the mucous membrane of the cervical canal, most of which is caused by pathogenic bacterial infections. Inflammation of the cervix can cause cervical hypertrophy accompanied by cervical engorgement, and the stimulation of inflammation can also cause pain in the lower abdomen. 3. Endometriosis: endometriosis refers to the endometrial tissue growth in parts other than the endometrium, ectopic endometrial foci of localized edema, bleeding, stimulation of the peritoneum, so there will be abdominal pain during menstruation, and in some cases, the pain will occur 1~2 days before menstruation, and may radiate to the lumbar-sacral region, the perineum, the anus, and thighs, and so on. There are more causes of pain in the middle of the abdomen, it is recommended to go to the hospital for detailed examination and symptomatic treatment for the cause.