Lower abdominal pain after menstruation is considered to be related to chronic pelvic inflammatory disease, ovarian cysts, and intrauterine device detachment. 1. Chronic pelvic inflammatory disease: If the patient has chronic pelvic inflammatory disease, due to the body’s resistance will be reduced after menstruation, so it may cause an acute attack of pelvic inflammatory disease, and leucorrhea, abdominal pain and other discomforts. 2. Ovarian cysts: for patients with ovarian cysts, the menstrual cycle may cause changes in the position of the uterus and other organs, which may lead to the torsion of the ovarian cysts, and the patients will experience persistent pain in the lower abdomen. 3. Intrauterine device detachment: For women who have already had an IUD, due to the stripping of the uterine lining and the flushing of menstrual blood, it is possible to cause the device to fall off, and if it is embedded in the cervix, it will stimulate the local nerves and cause pain and discomfort. It is recommended to go to the gynecology department of a regular hospital, complete the relevant examinations, and then take active treatment under the guidance of the doctor after clarifying the cause of the disease.