Dysmenorrhea with IUD is considered to be related to primary dysmenorrhea and secondary dysmenorrhea. 1. Primary dysmenorrhea: some patients may have primary dysmenorrhea before the IUD is inserted, and then they may also have dysmenorrhea after the IUD is inserted, which is considered to be related to factors such as increased prostaglandin content in the endometrium, excessive uterine inclination, and uterine dysplasia. 2. Secondary dysmenorrhea: some patients may have secondary dysmenorrhea after the IUD, mainly due to the damage caused by the IUD, secondary infection, and mismatch between the IUD and the uterine cavity. There may also be other reasons for dysmenorrhea after the IUD, such as pelvic infection, endometriosis, etc., which can also cause dysmenorrhea, so it is necessary to cooperate with the doctor to improve the examination and determine the cause before treatment.