Risk factors for ectopic pregnancy include previous ectopic pregnancy, current intrauterine device use, prior fallopian tube surgery, previous pelvic inflammatory disease and a prior history of infertility. Abdominal pain is the most common symptom, followed by amenorrhea or vaginal bleeding, nausea, vomiting, syncope and dizziness. Referred shoulder pain following the onset of abdominal pain is characteristic of intraperitoneal bleeding and, in the appropriate clinical setting, strongly suggests a ruptured ectopic pregnancy. A coordinated evaluation includes measurement of serum human chorionic gonadotropin concentration and transabdominal or, preferably, transvaginal ultrasonography. Treatment is primarily by one of a variety of surgical techniques. Medical therapy with methotrexate or other drugs is currently under investigation.