Clinical factors affecting the accuracy of ultrasonography in symptomatic first-trimester pregnancy.
OBJECTIVE
To evaluate factors associated with accuracy of initial ultrasonography in patients with symptomatic first-trimester pregnancy.


METHODS
Ultrasound diagnosis in the emergency department was compared with an ultimate clinical diagnosis in women in need of a gynecologic consult. The sensitivity, specificity, positive predictive values, and accuracy of the initial ultrasound impression were calculated and stratified by criteria of diagnosis, serum human chorionic gonadotropin (hCG) levels, pain, and bleeding.


RESULTS
Eighteen hundred eighty women were evaluated. Overall accuracy of initial ultrasound diagnosis was 78%. A probable ultrasound diagnosis of ectopic pregnancy (adnexal mass without the presence of a yolk sac or embryo) resulted in a higher sensitivity (42.1% compared with 13.2%: P<.001) but a lower positive predictive value (82.7% compared with 98%: P<.01) compared with a definite diagnosis. A probable ultrasound diagnosis of intrauterine pregnancy (double decidual sign without yolk sac or embryo) resulted in a higher sensitivity (36.0% compared with 4.0%; P<.001) and lower positive predictive value (58.8% compared with 87.0%; P>.001) compared with a definite diagnosis. The sensitivity (34.3% compared with 75.9%; P<.01) and positive predictive value (80.4% compared with 91.5%; P=.02) were lower for diagnosis of ectopic pregnancy when serum hCG level was less than 2,000 milli-international units/mL. Ultrasonography was less accurate when bleeding was the chief complaint (72.7% compared with 84.8% P<.006) but not substantially altered by pain as a chief complaint (78.0 compared with 77.8% P>.99).


CONCLUSIONS
A substantial number of misdiagnoses can occur when initial ultrasound diagnosis of intrauterine pregnancy or ectopic pregnancy is made without evidence of a yolk sac or embryo, when hCG values are low, or when a patient has significant bleeding.


METHODS
II.
From the Departments of Obstetrics and Gynecology and Emergency Medicine, Center for Clinical Epidemiology and Biostatistics, Philadelphia, Pennsylvania.
Kurt T
KT
Barnhart
Courtney A
CA
Fay
Maria
M
Suescum
Mary D
MD
Sammel
Dina
D
Appleby
Alka
A
Shaunik
Anthony J
AJ
Dean
D000293:Adolescent; D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood; D015331:Cohort Studies; D003951:Diagnostic Errors / Q000706:statistics & numerical data; D004632:Emergency Medical Services / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000000981:diagnostic imaging*; D011261:Pregnancy Trimester, First; D016216:Ultrasonography, Prenatal / Q000706:statistics & numerical data; D055815:Young Adult
D006063:Chorionic Gonadotropin
Barnhart KT. Clinical practice. Ectopic pregnancy. N Engl J Med 2009;361:379–87.
Wittels KA, Pelletier AJ, Brown DF, Camargo CA Jr. United States emergency department visits for vaginal bleeding during early pregnancy, 1993–2003. Am J Obstet Gynecol 2008;198:523.el–6.
Goldstein SR, Snyder JR, Watson C, Danon M. Very early pregnancy detection with endovaginal ultrasound. Obstet Gynecol 1988;72:200–4.
Barnhart K, Mennuti MT, Benjamin I, Jacobson S, Goodman D, Coutifaris C. Prompt diagnosis of ectopic pregnancy in an emergency department setting. Obstet Gynecol 1994;84:1010–5.
Tayal VS, Cohen H, Norton HJ. Outcome of patients with an indeterminate emergency department first-trimester pelvic ultrasound to rule out ectopic pregnancy. Acad Emerg Med 2004;11:912–7.
Kirk E, Papageorghiou AT, Condous G, Tan L, Bora S, Bourne T. The diagnostic effectiveness of an initial transvaginal scan in detecting ectopic pregnancy. Hum Reprod 2007;22:2824–8.
Condous G, Okaro E, Khalid A, Lu C, Van Huffel S, Timmerman D, et al. The accuracy of transvaginal ultrasonography for the diagnosis of ectopic pregnancy prior to surgery. Hum Reprod 2005;20:1404–9.
Peisner DB, Timor-Tritsch IE. The discriminatory zone of beta-hCG for vaginal probes. J Clin Ultrasound 1990;18:280–5.
McRae A, Edmonds M, Murray H. Diagnostic accuracy and clinical utility of emergency department targeted ultrasonography in the evaluation of first-trimester pelvic pain and bleeding: a systematic review. CJEM 2009;11:355–64.
Kaplan BC, Dart RG, Muskos M, Kuligowska E, Chun B, Adel Hamid M, et al. Ectopic pregnancy: prospective study with improved diagnostic accuracy. Ann Emerg Med 1996;28:10–7.
Mateer JR, Aiman EJ, Brown MH, Olson DW. Ultrasonographic examination by emergency physicians of patients at risk for ectopic pregnancy. Acad Emerg Med 1995;2:867–73.
Jaspan D, Giraldo-Isaza M, Dandolu V, Cohen AW. Compliance with methotrexate therapy for presumed ectopic pregnancy in an inner-city population. Fertil Steril 2010;94:1122–4.
Lok IH, Neugebauer R. Psychological morbidity following miscarriage. Best Pract Res Clin Obstet Gynaecol 2007;21:229–47.
Barnhart KT, Simhan H, Kamelle SA. Diagnostic accuracy of ultrasound above and below the beta-hCG discriminatory zone. Obstet Gynecol 1999;94:583–7.