Endometrial stripe thickness as a predictor of ectopic pregnancy

Objective: To evaluate the potential utility of endometrial stripe thickness in predicting pregnancy outcome in women with an hCG less than a discriminatory zone. Design: Retrospective case review. Setting: University emergency department. Patients: Women who presented with symptomatic early pregnancies after a spontaneous conception with an hCG level less than a discriminatory zone evaluated to rule out an ectopic pregnancy (EP). Interventions: Measure endometrial stripe thickness by transvaginal ultrasound. Main Outcome Measures: Initial endometrial stripe thickness was correlated to eventual pregnancy outcomes. Results: The mean initial endometrial stripe thickness of patients eventually diagnosed with an intrauterine pregnancy (13.42 +/- 0.68 mm), spontaneous abortion (9.28 +/- 0.88 mm), and an EP (5.95 +/- 0.35 mm) were all statistically different from each other. Ninety-seven percent of pregnancies found to have an endometrial stripe thickness less than or equal to 8 mm were abnormal (EP or spontaneous abortion). Conclusions: This study suggest a role of the evaluation of the endometrial stripe thickness in the detection of abnormal pregnancies in patients presenting for evaluation of a symptomatic early pregnancy with an hCG below a discriminatory zone. Initial endometrial stripe thickness measured in patients with an EP is significantly thinner than in those with an intrauterine pregnancy.