For pregnancy to happen, the ovary has to release an egg into the fallopian tube, where it stays for about 24 hours. There it has to come in contact with a sperm to be fertilized. The fertilized egg stays in the fallopian tube for 3 or 4 days before it heads to the uterus. There it attaches to the lining and continues to grow until a baby is born. But if the fertilized egg implants in your fallopian tube or somewhere else in your abdomen, you end up with what’s called an ectopic pregnancy. In these cases, the pregnancy can’t continue normally, and it requires emergency treatment.