What causes an ectopic pregnancy?
An ectopic pregnancy results from a fertilized egg’s inability to work its way quickly enough down the fallopian tube into the uterus. An infection or inflammation of the tube might have partially or entirely blocked it. Pelvic inflammatory disease (PID), which can be caused by gonorrhea or chlamydia, is a common cause of blockage of the fallopian tube. Endometriosis (when cells from the lining of the uterus implant and grow elsewhere in the body) or scar tissue from previous abdominal or fallopian surgeries can also cause blockages. More rarely, birth defects or abnormal growths can alter the shape of the tube and disrupt the egg’s progress.