Suspected ectopic pregnancy: expectant management in patients with negative sonographic findings and low serum hCG concentrations.

Between July 1989 and December 1994, we performed a prospective study in 265 patients with suspected ectopic pregnancy to assess the value of expectant management in patients with negative transvaginal sonographic findings and low serum human chorionic gonadotropin (hCG) concentrations. All patients had serum hCG concentrations < 1500 IU/l. Eventually, ectopic pregnancy was diagnosed in 68 patients (25.6%), intrauterine pregnancy in 81 patients (30.6%) and trophoblast in regression in 116 patients (43.8%). Test results of our diagnostic strategy, that integrated the results of serial transvaginal sonography, serum hCG monitoring and expectant management, were good: sensitivity 90%, specificity 98%, likelihood ratio of a positive test result 45 and likelihood ratio of a negative test result 0.1. Expectant management in patients with suspected ectopic pregnancy and low serum hCG concentrations proved to be safe, and it enabled us to avoid untimely invasive interventions in patients with an early intrauterine pregnancy or with trophoblast in regression.