A birth control device 15mm from the bottom of the uterus is usually normal. The birth control device is a contraceptive device placed at the bottom of the uterine cavity of a woman, which mainly plays a role in contraception. Under normal circumstances, it is normal for a woman’s IUD to be placed 10-20mm from the bottom of the uterus, but this varies from woman to woman as each woman’s condition is different. When the distance of the IUD from the uterine fundus exceeds 20mm during the abdominal ultrasound examination, accompanied by symptoms such as pain in the lower abdomen and waist, vaginal bleeding, etc., it is mostly due to the displacement of the IUD. Therefore, women with IUDs are advised to have regular checkups and if any discomfort occurs, they are advised to go to the hospital for treatment in time to avoid delaying their condition.