Detection of ectopic pregnancy in an outpatient population: The role of the beta-HCG level

Abstract

A retrospective analysis was made of 265 female outpatients who initially presented to an emergency department with a complaint of amenorrhea, vaginal bleeding, or abdominal/pelvic pain. The patients were discharged from the emergency department pending results of a serum pregnancy test. Forty-five of the patients were subsequently found to have an elevated (>5 mIU/mL) beta human chorionic gonadotropin (HCG) level. Six of the patients had an ectopic pregnancy; their beta HCG levels ranged from 19 to 265 mIU/mL. A detectable beta HCG level less than 500 mIU/mL had a 33076 probability of an ectopic pregnancy in the study group. Historical features, physical examination, and laboratory parameters were of limited value for identification of minimally symptomatic outpatients at risk for an ectopic pregnancy. No study patient had a systolic blood pressure of less than 86 mm Hg on presentation. A comparison group of 29 patients admitted to the hospital directly from the emergency department with a diagnosis of “rule out ectopic pregnancy” during the same time interval was identified. Nine of the directly admitted patients were found to have ectopic pregnancies. A statistically greater proportion of the directly admitted patients had a hematocrit less than 35% and a positive urine (tube) pregnancy test than that found for the study group. Five of the comparison group patients were noted to have a systolic blood pressure of less than or equal to 80 mm Hg. The beta HCG was found to be an essential tool in the evaluation of potential ectopic pregnancy in patients with minimal symptomatology.