Ectopic pregnancy can occur with an IUD because the IUD stops intrauterine pregnancy, but it does not stop ectopic pregnancy. Ectopic pregnancy is when the fertilized egg is deposited and planted in different parts of the fallopian tube, such as the umbilical, jugular, isthmus, and interstitial parts of the fallopian tube. For why ectopic pregnancy occurs, it is normally due to the sperm passing through the uterus to the fallopian tube at the umbilical end of the fallopian tube, waiting for the ovum to be discharged, and forming a fertilized egg in the juxta-pubic area of the fallopian tube. With tubal peristalsis, the fertilized egg reaches the uterine cavity for implantation. If the newborn fertilized egg stays in the oviduct for more than 72 hours, or the fallopian tube has inflammation or narrowing, the fertilized egg can not pass through the fallopian tube to the uterine cavity, the fertilized egg is planted in the fallopian tube, and ectopic pregnancy occurs at this time. So on the birth control ring should also pay attention to menstruation, on the delayed menstruation or not come to tide, should go to the hospital in time to check except pregnancy, especially except ectopic pregnancy.