Emergency physician ultrasonography for evaluating patients at risk for ectopic pregnancy: a meta-analysis

Ectopic pregnancy is a common concern in emergency departments (EDs) and remains the leading cause of first-trimester mortality. Pelvic ultrasonography by emergency physicians has been investigated as a diagnostic test for ectopic pregnancy. We present a meta-analysis of the use of emergency physician ultrasonography in the evaluation of patients at risk of ectopic pregnancy.

A structured search was performed of both MEDLINE and EMBASE. Inclusion criteria were that (1) the study reported original research on ED patients at risk for ectopic pregnancy; (2) an emergency physician performed and interpreted the initial pelvic ultrasonography; and (3) follow-up was conducted on all patients. Sensitivity was defined as the proportion of patients with ectopic pregnancy for which ED ultrasonography demonstrated no intrauterine pregnancy. A random-effects model was used to obtain summary test characteristics.

The initial search showed 576 publications, abstract review yielded 60 with potential relevance, and 10 studies were included. There was a total of 2,057 patients, of whom 152 (7.5%) had ectopic pregnancy. The pooled sensitivity estimate was 99.3% (95% confidence interval [CI] 96.6% to 100%), negative predictive value was 99.96% (95% CI 99.6% to 100%), and negative likelihood ratio was 0.08 (95% CI 0.025 to 0.25), all without significant heterogeneity.

The results of this meta-analysis suggest that in a wide variety of clinical settings, the use of bedside ultrasonography performed by emergency physicians as a diagnostic test for ectopic pregnancy provides excellent sensitivity and negative predictive value. Visualization of an intrauterine pregnancy by an emergency physician is generally sufficient to rule out ectopic pregnancy.