If you become pregnant with an intrauterine device (IUD), you should have an ultrasound because there is a higher risk of ectopic pregnancy. The IUD makes the uterus inhospitable for a fertilized egg and therefore if a pregnancy does occur, it is more likely that it will occur outside the uterus.
If the ultrasound shows that the pregnancy is in the uterus, the IUD should ideally be removed before using abortion pills.
If the ultrasound shows an ectopic pregnancy, then you should seek help from hospital. Abortion pills will not terminate an ectopic pregnancy.