Postmenstrual abdominal pain may be caused by adnexitis, pelvic inflammatory disease, urinary system and other reasons. 1. Adnexitis: not paying attention to personal hygiene during menstruation, using unclean sanitary napkins and pads, taking a bath during menstruation, and having sex during menstruation can cause inflammation due to the invasion of pathogens, leading to postmenstrual abdominal pain. 2. Pelvic inflammatory disease: it refers to the inflammation of the female reproductive organs, connective tissues around the uterus and pelvic peritoneum, then it will cause the symptoms of postmenstrual abdominal pain. 3. Urinary system: inflammation and stones in the urinary system can lead to inflammatory irritation or obstruction of the ureter, and the phenomenon of postmenstrual abdominal pain. Therefore, in the clinic, when the patient appears to have postmenstrual abdominal pain, should go to the regular hospital in time, ask the doctor to clarify the cause of the disease, and then carry out the corresponding treatment.