You can find this answer by Googling that question. But, as someone who answers questions, I'll write it within my own words.
An ectopic pregnancy is when the egg is attached somewhere else aside from the uterus; the normal resting spot for the fertilized egg to begin growing. Usually, in an ectopic pregnancy, the egg goes into a fallopian tube which is obviously not where the egg is meant to be growing, so the embryo usually cannot form and continue to grow. Since the egg is already inside a tube, there is no possible way for it to survive. This doesn't occur that often, but that's not to say it doesn't occur at all.
