I hope you come back and share more information for why you are asking this question! In general, they CAN move. This article talks about what to look for to analyze if the IUD has moved. https://www.healthline.com/health/iud-moved If you suspect it has moved, get to your doctor who can assess quickly and take care of that. The actual rate is said to be .5% to a full 8% of the time they move. Not a ton but they definitely can.