As with other progestin-only methods, persistent ovarian follicles can occur. They do not require treatment or removal of the IUS, and they usually resolve spontaneously. However, regular follow-up by ultrasound is recommended until cysts disappear. Table 1 shows some of the signs that complications may have occurred. To locate the radiopaque IUS, begin by using transvaginal ultrasound.
Most expulsions occur in the first months following insertion, with decreasing frequency thereafter.