An ectopic pregnancy occurs when the fertilized egg attaches itself in a place other than inside the uterus. Most cases occur in the fallopian tube and are thus sometimes called tubal pregnancies. The fallopian tubes are not designed to hold a growing embryo; thus, the fertilized egg in a tubal pregnancy cannot develop properly and must be treated.
https://americanpregnancy.org/healthy-pregnancy/pregnancy-complications/ectopic-pregnancy-839/

