The main purpose of the IUD is to provide contraception. When the ring is dislodged, many patients do not have any particularly noticeable symptoms. Some patients may experience abdominal cramping, back pain, or a small amount of vaginal bleeding, and sometimes an increase in the amount of leukorrhea, while some patients may have no symptoms. In clinical practice, some patients may come to the hospital with symptoms such as nausea and vomiting, and after ultrasound examination, they find that they are pregnant, and only then do they know that the ring has fallen off. For example, in patients with endometriosis or adenomyosis, the painful menstruation effect will be significantly improved after the IUD is applied. If the IUD is dislodged, the patient will experience periodic and progressive abdominal pain during menstruation, and the dislodged IUD will be detected by ultrasound after the patient has been seen in the hospital. Therefore, it is recommended to perform ultrasound examination after 1 month after the IUD to check whether the ring position is normal and to check whether the ring is dislodged to avoid unnecessary consequences.