A woman's two fallopian tubes lead upward from each upper side of the uterus and end near the ovaries. When an egg is released by an ovary (ovulation), it travels down a fallopian tube toward the uterus.
After ovulation, egg fertilization usually happens in a fallopian tube. The fertilized egg then travels to the uterus, where it implants and grows. If a woman's fallopian tubes are blocked by scar tissue, such as from pelvic inflammatory disease, she may be unable to become pregnant or have a tubal (ectopic) pregnancy.
WebMD Medical Reference from Healthwise