Abdominal adhesions are a common complication of surgery, occurring in up to 93% of people who undergo abdominal or pelvic surgery. Abdominal adhesions also occur in 10.4% of people who have never had surgery. Pelvic adhesions may involve any organ within the pelvis, such as the uterus, ovaries, fallopian tubes, or bladder, and usually occur after surgery. Pelvic inflammatory disease (PID) results from an infection (usually a sexually transmitted disease) that frequently leads to adhesions within the fallopian tubes. A woman's eggs pass through her fallopian tubes into her uterus for reproduction. Fallopian adhesions can lead to infertility and increased incidence of ectopic pregnancy in which a fetus develops outside the uterus.