A woman with an ectopic pregnancy has a developing pregnancy that is outside of the uterus. Ectopic pregnancies often occur in the Fallopian tube, where they are commonly referred to as a tubal pregnancy.

At the beginning of a pregnancy, the egg is fertilized as it passes through the fallopian tube. Then, the fertilized egg, or embryo, attaches to the inside of the uterus and starts to grow. An ectopic pregnancy refers to an embryo that does not reach the uterus: it starts to grow in another location. Ectopic pregnancies usually occur in one of the fallopian tubes, but ectopic pregnancies can occur in other locations inside the abdomen.