the fallopian tubes are a pair of tubes that connect to 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 the fallopian tubes are blocked by scar tissue, such as from pelvic inflammatory disease, you may be unable to become pregnant. or it may cause a tubal (ectopic) pregnancy.