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.

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. Any condition that causes scarring within the Fallopian tubes can increase the risk of tubal pregnancy.

Fallopian tube scarring may be caused by:

• Abdominal surgery
• Chlamydia infection
• Gonorrhea infection
• Pelvic inflammatory disease