Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding. Fewer than 50 percent of affected women have both of these symptoms. The pain may be described as sharp, dull, or cramp. Pain may also spread to the shoulder if bleeding into the abdomen has occurred. Severe bleeding may result in a fast heart rate, fainting, or shock. With very rare exceptions the fetus is unable to survive.
Risk factors for ectopic pregnancy include pelvic inflammatory disease, often due to chlamydia infection; tobacco smoking; prior tubal surgery; a history of infertility; and the use of assisted reproductive technology. Those who have previously had an ectopic pregnancy are at much higher risk of having another one. Most ectopic pregnancies (90%) occur in the fallopian tube, which are known as tubal pregnancies. Implantation can also occur on the cervix, ovaries, or within the abdomen. Detection of ectopic pregnancy is typically by blood tests for human chorionic gonadotropin (hCG) and ultrasound.
This may require testing on more than one occasion. Ultrasound works best when performed from within the vagina. Other causes of similar symptoms include: miscarriage, ovarian torsion, and acute appendicitis.