Beta‐Human Chorionic Gonadotropin Levels and the Likelihood of Ectopic Pregnancy in Emergency Department Patients with Abdominal Pain or Vaginal Bleeding

Abstract

Strategies for diagnosing ectopic pregnancy that defer endovaginal ultrasound in women with suggestive symptoms and serum beta-human chorionic gonadotropin (bhCG) levels less than 1,500 mIU/mL ignore the increased risk of ectopic pregnancy in these patients. Objective: To quantify this increased risk by establishing and comparing the b-hCG distributions of symptomatic women with ectopic pregnancies, abnormal intrauterine pregnancies, and normal intrauterine pregnancies. Methods: The authors reviewed the records of a cohort of women who visited an urban emergency department (ED) during a 34-month period with abdominal pain or vaginal bleeding and nonzero quantitative b-hCG levels. Explicit criteria were used to determine whether the pregnancy ultimately turned out to be intrauterine and normal, intrauterine and abnormal, or ectopic. Probability distributions were compared using frequency distributions, receiver operating characteristic (ROC) curves, and likelihood ratios. Results: Of 730 ED patients included in the analysis, 96 (13%) had ectopic pregnancies, 253 (35%) had abnormal intrauterine pregnancies, and 381 (52%) had normal intrauterine pregnancies. The b-hCG distributions of patients with ectopic pregnancies and abnormal intrauterine pregnancies were similar and much lower than the b-hCG distribution of patients with normal intrauterine pregnancies. A b-hCG level less than 1,500 mIU/mL more than doubled the odds of ectopic pregnancy (likelihood ratio ¼ 2.24). Of the 158 patients with b-hCG below 1,500 mIU/mL, 40 (25%; 95% confidence interval [CI] ¼ 19% to 32%) had ectopic pregnancies, and only 25 (16%; CI ¼ 11% to 22%) had normal intrauterine pregnancies. Conclusions: In women with pain or bleeding and serum b-hCG levels less than 1,500 mIU/mL, the risk of ectopic pregnancy is substantially increased, while the likelihood of normal intrauterine pregnancy is low.

Clinical Policy: Critical Issues in the Initial Evaluation and Management of Patients Presenting to the Emergency Department in Early Pregnancy

“…The prevalence of ectopic pregnancy in symptomatic emergency department (ED) patients is as high as 13% in some series, which is much higher than the incidence in the general population. 2,3 Ultrasound is part of the usual workup for patients with symptomatic early pregnancy. A meta-analysis 4 and systematic review 5 both found that bedside ultrasound performed by emergency physicians can be used as a screening tool for ectopic pregnancy; however, a review of the evidence supporting this practice is beyond the scope of this policy.…”

Ultrasound Criteria for Diagnosis of Early Pregnancy Failure and Ectopic Pregnancy

“…1 In emergency room populations, the prevalence is increased to 7 to 13%. 38,39 The overall sensitivity and specificity for diagnosing ectopic pregnancy using transvaginal ultrasound ranges from 87 to 93% and from 94 to 99%, respectively. [40][41][42] Ectopic pregnancies may occur within the cervix, ovary, uterine cornua, cesarean section scar, and abdomen.…”

“…44,45 When the bhCG is below 1500, sonography is still useful. 38,46 Although an early intrauterine gestation cannot be visualized, an ectopic pregnancy or other findings suggestive of an ectopic pregnancy may be apparent. Almost half of ectopic pregnancies present with a bhCG below 1500 and many are visible on ultrasound.…”

A four-year survey on unexpected pregnancy diagnoses in a large urban emergency department in Parma, Italy

“…Emergency physicians frequently manage female patients with abdominal pain and/or vaginal bleeding in the first trimester of pregnancy, who may be aware or unaware of their pregnancy status. In addition to ovarian torsion or another acute pelvic pathology, one of the primary concerns in this group of patients is an ectopic pregnancy, the prevalence of which reaches 13% among symptomatic ED patients; this rate is substantially higher than that in the general population [8]. Given the increasing availability of bedside ultrasound in EDs, this diagnostic technique is often used routinely in the evaluation of patients with suspected ectopic pregnancy.…”