Monday, November 5, 2007

This presentation is part of : Strategies for Utilization of Research
The Relationship between Quantitative B-hCG Levels and Ectopic Pregnancy in an Emergency Department Cohort: Development of an Evidence-Based Clinical Pathway
Tania D. Strout, RN, BSN1, Michael R. Baumann, MD, FACEP2, and Rebecca B. Bloch, MD2. (1) Emergency Department, Maine Medical Center, Portland, ME, USA, (2) Department of Emergency Medicine, Maine Medical Center, Portland, ME, USA
Learning Objective #1: 1. Discuss the concept of the “discriminatory zone” in the evaluation of women at risk for ectopic pregnancy.
Learning Objective #2: 2.Discuss the relationship between quantitative beta-human chorionic gonadotropin and ectopic pregnancy.

Purpose: Ectopic pregnancy is a serious condition with significant morbidity and mortality. Despite evidence that B-hCG levels do not fluctuate as expected in women with ectopic or abnormal pregnancies, many hospitals use the concept of a “discriminatory zone” where women with a B-hCG below a cut-point do not receive a transvaginal ultrasound. The purpose of this investigation was to evaluate the relationship between quantitative B-hCG levels and ectopic pregnancy in an emergency department (ED) population. Methods: Rodgers’ Science of Unitary Human Beings served as the theoretical framework for this IRB exempted health records survey. Data for women presenting to the ED with vaginal bleeding and/or abdominal pain who underwent both B-hCG testing and transvaginal ultrasound for the period from 10/1/03 to 9/30/05 was collected and analyzed. Results: 337 visits meeting inclusion criteria were identified.  Twenty-one subjects (6.23%) had confirmed ectopic pregnancy, 10 were ruptured and 11 were unruptured. No statistically significant difference in mean B-hCG level was identified in those subjects with ruptured versus unruptured ectopic pregnancy (t=0.115, df=19, p=0.910). A statistically significant difference in days gestation was noted when comparing ruptured and unruptured ectopics (t=3.086, df=18, p=0.006). Mean days gestation for women with ruptured ectopics were 32.8 +/- 12.3, 95% CI: 24.0 to 41.5 days, while days gestation for unruptured ectopic pregnancies were 48.1 +/- 9.78, 95% CI: 41.1 to 55.1. Conclusions: In this cohort, ectopic pregnancy was associated with low B-hCG levels. Both ruptured and unruptured ectopic pregnancy occurred at B-hCG levels below traditional cut-points. Low B-hCG levels should not be used to exclude the possibility of ectopic pregnancy in women with vaginal bleeding or abdominal pain and short-term gestation. The results of this study were used to create an evidence-based guideline for the evaluation of women presenting to the ED with symptoms suggestive of ectopic pregnancy.