Are gestational age and endometrial thickness alternatives for serum human chorionic gonadotropin as criteria for the diagnosis of ectopic pregnancy?

Objective: To compare gestational age and endometrial stripe thickness measurement with serum hCG measurement as criteria for the diagnosis of ectopic pregnancy (EP). Design: Prospective study. Setting: Two large teaching hospitals in Amsterdam, the Netherlands. Patient(s): Three hundred fifty-four consecutively seen pregnant patients who presented between September 1993 and April 1996 with suspected EP and in whom transvaginal ultrasonogram showed no intrauterine pregnancy or EP. Ultrasonography was performed by one of the study investigators or, during shifts, by the resident on call. Intervention(s): None. Main Outcome Measure(s): The accuracy of gestational age, endometrial stripe thickness, and serum hCG measurement in the diagnosis of EP was evaluated with receiver operating characteristic curve analysis. Result(s): Gestational age and endometrial stripe thickness could not discriminate between patients with EP and patients without EP, whereas serum hCG had an acceptable area under the receiver operating characteristic curve. Conclusion(s): Gestational age and endometrial thickness are not useful in the diagnosis of EP. Serum hCG measurement is the diagnostic instrument of choice in patients with suspected EP when transvaginal ultrasonography does not reveal a diagnosis.