Chances are your IUD is not going to move after it is inserted however, just to be safe doctors recommended a yearly ultrasound to be certain. In most cases, any pregnancy that results while using an IUD is from the original insertion being misplaced. Once an IUD is inserted, the doctor will usually do a pelvic exam to make sure it is in the correct position. There is always a slight possible that the IUD can move anytime after placement however, the movement is usually the result of an injury in the pelvic region.
The study looked at forty-two women who had become pregnant after having an IUD inserted. Thirty-six of the women had IUDs that were placed and a visual 2D ultrasound was used to ensure correct placement. Of the thirty-six IUDs that were verified with an ultrasound, fifteen of them were correctly positioned and twenty-one of the IUDs were not in the correct position. Out of the thirty-six women who became pregnant with the IUD the women had either an ectopic pregnancy, miscarriage or a pregnancy of an unknown location or chemical pregnancy (proof of pregnancy but no sac therefore, no fetus.)
When a woman is not expecting to become pregnant and she does, it is an emotional roller coaster especially when it ends in an ectopic (dangerous situation), miscarriage or pregnancy of unknown location it can be very difficult for the woman and the partner. If a simple, ultrasound is all that is needed to prevent this (in most cases it would) then it is well worth it.