When the IUD is displaced, symptoms such as lower abdominal pain, small amount of vaginal bleeding, increased vaginal discharge, incomplete menstruation, and pregnancy with the IUD may occur. The IUD in the uterine cavity mainly serves to change the nature of the endometrium and the environment of the uterine cavity, thus interfering with the fertilized egg to achieve the purpose of contraception. The IUD is supposed to be at the bottom of the uterus in the middle of the uterine cavity, and changes in its position such as downward shift, deviation, and myometrial embedding change the effect on the uterine cavity and the endometrium. If the endometrium is stimulated to shed irregularly, causing bleeding, abdominal pain, and menstrual changes. The downward displacement stimulates the cervical glands, causing inflammatory reaction, increased secretion, and soreness and pain in the lower back. If the IUD is directly embedded in the myometrium, in addition to the above symptoms, significant dysmenorrhea will occur. The displaced IUD has lost its normal contraceptive function, so it is easy to have an unwanted pregnancy or even an ectopic pregnancy.