Ectopic pregnancy is defined as any pregnancy outside the uterus and is a leading cause of maternal mortality in the first trimester. The incidence of ectopic pregnancy has increased from 4.5 cases per 1,000 pregnancies in 1970 to 19.7 cases per 1,000 pregnancies in 1992 in part due to improved diagnostics. Risk factors for ectopic pregnancy include pelvic inflammatory disease (PID), previous ectopic pregnancy, endometriosis, previous tubal surgery, previous pelvic surgery, infertility and infertility treatments, uterotubal anomalies, history of in utero diethylstilbestrol, and cigarette smoking. Clinical presentation can be variable depending on the location of the ectopic pregnancy but the hallmark is cramping abdominal pain with vaginal spotting, usually occurring 6-8 weeks after the last normal menstrual cycle. Diagnostic evaluation includes quantitative serum beta-HGC and pelvic ultrasound. A gestational sac can be consistently visualized with transabdominal ultrasound when the serum beta-HCG is greater than 6,500 mIU/ml and can be visualized with transvaginal ultrasound when serum beta-HCG is greater than 1,500 mIU/ml. If transvaginal ultrasound does not reveal an intrauterine gestational sac when the beta-HCG is greater than 1,500 mIU/ml an ectopic pregnancy can be suspected. If a gestational sac containing a yolk sac or fetal pole is identified outside of the endometrial cavity the diagnosis of ectopic pregnancy is confirmed. The most frequent location of ectopic pregnancy it tubal (97%) with an ampullary position most common. Other locations include cornual (3%), ovarian (1%), cervical (very rare), fimbrial (very rare) and abdominal (very rare). Uterine ultrasound features with ectopic pregnancy include a normal uterus, thick decidual cast with no gestational sac or pseudogestational sac. Extrauterine sonographic features include identification of a live embryo outside of the uterus, tubal ring sign, complex adnexal mass, simple adnexal cyst or free fluid in the cul de sac (anechoic or echogenic). Ectopic pregnancy is not excluded with a normal transvaginal ultrasound and should be considered an indeterminate study. A normal intrauterine pregnancy with a coexistent ectopic pregnancy (heterotopic pregnancy) is unlikely. The rate of heterotopic pregnancy in Europe and the United States is one in 2,600 pregnancies and in patients undergoing fertility treatments this increases to 3%.

Management of ectopic pregnancy includes medical and surgical therapy. If an ectopic pregnancy is diagnosed early with certainty and the ectopic mass is less than 3.5 cm the patient can be treated with medications such as methotrexate. Patients with beta-HCG levels greater than 1,500 mIU/ml may not respond to therapy and patients with beta-HCG levels greater than 5,000 mIU/ml usually fail medical therapy. Multiple other criteria for methotrexate therapy exist. Laparotomy is the preferred treatment for unstable patients but in hemodynamically stable patients laparoscopy with salpingostomy is preferred. Salpingectomy is performed if necessary. The most common complication following surgery is recurrent ectopic pregnancy.