Emergency physicians frequently evaluate and manage patients with abdominal pain and/or vaginal bleeding during the first trimester of pregnancy. Although a variety of pathologies may cause these symptoms, the primary concern of the physician is to identify conclusively those patients with an ectopic pregnancy. In recent years bedside ultrasound (performed in the ED by the emergency clinician rather than in the radiology department) has become more common, but approaches to diagnosing ectopic pregnancy still vary considerably because of differing availability of ultrasound across departments or at different times of day.
Explore This IssueACEP News: Vol 31 – No 10 – October 2012
These patients present a diagnostic challenge because they frequently present before an intrauterine or extrauterine pregnancy can be definitively seen with ultrasound. Therefore, many algorithms incorporate a quantitative b-hCG level and apply the principle of the “discriminatory threshold,” generally defined as the level at which the sensitivity of ultrasound approaches 100% for the detection of intrauterine pregnancy. This threshold is commonly reported as ranging from 1,000 mIU/mL to 2,000 mIU/mL, and the presumptive diagnosis of ectopic pregnancy traditionally has been made if an intrauterine pregnancy is not visualized when the serum b-hCG is above this threshold.
In the September 2012 issue of the Annals of Emergency Medicine, ACEP published a clinical policy on the evaluation and management of patients in early pregnancy, which is a revision of a policy written in 2003. The updated policy examines three critical questions faced by emergency clinicians. The first two questions are driven by ambiguities that commonly arise when using the b-hCG and the bedside ultrasound to identify ectopic pregnancy. The third critical question explores the implications of patients receiving methotrexate for confirmed or suspected ectopic pregnancy. Another question that often arises in the management of these patients is whether to administer anti-D immunoglobulin to those who are Rh-negative. However, because no new quality evidence on this topic was identified during the literature search, the patient management recommendations from 2003 remain unchanged and are not discussed further in the 2012 policy.
Recommendations (Level A, B, or C) for patient management are provided based on the strength of evidence using the Clinical Policies Committee’s well-established methodology:
Level A recommendations represent patient management principles that reflect a high degree of clinical certainty
Level B recommendations represent patient management principles that reflect moderate clinical certainty
Level C recommendations represent other patient management strategies based on Class III studies, or in the absence of any adequate published literature, based on consensus of the members of the Clinical Policies Committee
Question 1: Should the emergency physician obtain a pelvic ultrasound in a clinically stable pregnant patient who presents to the ED with abdominal pain and/or vaginal bleeding and a b-hCG level below a discriminatory threshold?
Level A recommendations. None specified.