Correlation of β-human chorionic gonadotropin with ultrasound diagnosis of ectopic pregnancy in the ED.

Women with ectopic pregnancies tend to have lower β-human chorionic gonadotropin (β-hCG) levels than women with intrauterine pregnancies (IUP) [1]. Transvaginal ultrasound (TVUS) is capable of detecting IUPs when β-hCG levels are greater than 1500 mIU/mL, the so-called discriminatory zone [2–4]. When serum β-hCG levels are less than 1500 mIU/mL and no IUP is detected, possibility of ectopic pregnancy or early IUP exists. Because of the discriminatory zone, emergency physicians often opt not to perform ultrasound on patients whose β-hCG level is less than 1500 mIU/mL. Many ectopic pregnancies, however, are detected by emergency TVUS with β-hCG levels less than 1500 mIU/mL [1,5]. Our primary objective was to determine the frequency of patients with β-hCG levels less than 1500 mIU/mL who are diagnosed with ectopic pregnancy by emergency ultrasound. Our secondary objective was to evaluate the presenting complaints of women diagnosed with ectopic pregnancy and any associated risk factors. This retrospective chart review, approved by the institutional review board, was conducted at an academic center with emergency medicine physicians trained and credentialed in TVUS. Charts with a discharge diagnosis of ectopic pregnancy, miscarriage, pregnancy, abdominal pain, and/or vaginal bleeding were reviewed. Inclusion criteria were positive pregnancy with documented β-hCG level and ultrasound performed at the time of the emergency department (ED) visit. There were no exclusion criteria. Ectopic pregnancy was defined by sonographic criteria consistent with an ectopic pregnancy and reported diagnosis of ectopic pregnancy. Ultrasounds performed by emergency physicians as well as radiology and obstetrics-gynecology (OB) were included. From October 2007 through June 2010, 3707 charts were identified and reviewed. Data from 876 patients meeting inclusion criteria were recorded on standardized data sheets and entered into Microsoft Excel 2008 for analysis. Of the 876 patients, 47 were diagnosed with ectopic pregnancy by emergency ultrasound, representing 5.4% of the total number of pregnancies. Emergency medicine physicians diagnosed 22 (46.8%) of 47 ectopic pregnancies by emergency ultrasound. Thirteen (27.7%) were diagnosed by ultrasounds performed by OB and 7 (14.9%) by radiology. Five (10.6%) had ultrasounds performed by both the emergency physician and either OB or radiology. Recorded β-hCG levels of the 47 ectopic pregnancies ranged from 125 to 68138 mIU/mL (Fig). Seven ectopic pregnancies (14.9%) were diagnosedwith β-hCG levels less than 500mIU/mL; 6 (12.8%), with βhCG levels between 500 and 1000 mIU/mL; and 2 (4.3%), with β-hCG levels between 1000 and 1500 mIU/mL. Overall, 15 ectopic pregnancies (31.9%) were diagnosed by ultrasound with β-hCG levels less than 1500 mIU/mL. Of the 32 ectopic pregnancies for which follow-up data were available, 87.5% were taken to the operating room and had confirmed surgical diagnosis of ectopic pregnancy, whereas 12.5% were treated