When a fertilized egg grows outside the uterus, usually in the fallopian tube, it is referred to as an ectopic pregnancy. This type of pregnancy causes the fallopian tube to eventually burst, leading to life-threatening bleeding. According to the American College of Obstetricians and Gynecologists, risk factors for such a pregnancy include the following: previous ectopic pregnancy, prior fallopian tube surgery, previous pelvic or abdominal surgery, certain STDs, pelvic inflammatory disease, endometriosis, smoking, becoming pregnant at 35 or older, infertility history, and the use of assisted reproductive technology. American College of Obstetricians and Gynecologists, May 2018