• 2% of all pregnancies.
• Occurs in up to 18% of ED 1^st trimester patients presenting with bleeding +/- abd pain.
• 9% of all pregnancy-related deaths and leading cause of maternal death in the 1^st  trimester.
• Abdominal pain and/or bleeding in the 1^st trimester = ectopic pregnancy (EP) until proven otherwise.
• 30% of patients presenting with bleeding and/or pain in the 1^st trimester will have a pregnancy of unknown location (PUL).
• PUL includes:
  • EP.
  • IUP – spontaneous abortion.
  • IUP – normal developing pregnancy.
• An approach to a “rule-out” ectopic includes:
  • Localization of pregnancy on US.
  • If PUL, risk stratification with serial β-hCG and TVUS until a diagnosis of IUP or EP.
  • Balancing the risk of ruptured ectopic and the risk of ending a viable, desired pregnancy.

• Classic triad: Pain (98%), amenorrhea (74%), and vaginal bleeding (56%).
• Ruptured ectopic:
  • Hemodynamic instability.
  • Peritoneal signs (rebound tenderness, cervical motion tenderness).
• May have normal vital signs and minimal tenderness.
• Localize the pregnancy with transabdominal U/S, then transvaginal U/S if necessary.
• IUP visualization on ED POCUS effectively rules out an ectopic.
• Heterotopic pregnancies are rare, but considered with assisted reproductive technologies, as probability is higher (around 1%).

Barash et al. (2014), AAFP2

Criteria for localization of pregnancy on US:

• If PUL, risk stratify using β-hCG:
  • A discriminatory thresholds of β-hCG indicates when IUP usually can be seen on US but the utility of this threshold has been challenged. Most recent recommended thresholds are:
    • Transvaginal US: β-hCG > 2000 – 3000 IU/L (especially before 7 weeks GA) OR the more conservative β-hCG > 3,500 IU/L suggested by American guidelines.
    • Bedside abdominal US: β-hCG > 6,500 IU/L
  • A β-hCG above the threshold and no IUP significantly increases the risk of ectopic.
  • An EP can rupture at any β-hCG level.
  • All symptomatic pregnant women presenting in the 1^st trimester should have an US, irrespective of β-hCG.

• If PUL, arrange an OB/GYN follow up and repeat β-hCG +/- TVUS in 48 hours.
  • β-hCG should rise > 55% over 48 hours in the first 7 weeks.
  • Failure to rise (falling or plateauing β-hCG) is indicative of a failing pregnancy (IUP or ectopic).
• Subsequent β-hCG measurements and TVUS should be obtained 2–7 days apart, depending on the pattern of change.
• The risk of rupture if there are no US findings of EP and no symptoms of rupture during diagnostic process is very low (0.03%). Therefore, there is limited risk in taking a few extra days to make a definitive diagnosis.

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Barash et al. (2014), AAFP

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Barash et al. (2014), AAFP

1. Relying on the classic triad of abdominal pain, vaginal bleeding, and missed menses to consider an ectopic.
2. Not considering a heterotopic pregnancy in a high-risk population when there is an IUP.
3. Not considering a ruptured ectopic pregnancy when a patient has already taken methotrexate.
4. Assuming an ectopic is ruled out with a low β-hCG.
5. Confusing a “double sac sign” in the uterus as an IUP, when it could be a pseudogestational sac or intrauterine cyst.
6. Assuming no products of conception on U/S signifies a completed spontaneous abortion, rather than an ectopic.
7. Failure to arrange adequate follow up if no IUP is seen and the U/S is indeterminate.

• Ectopic Pregnancy Scan Procedural Video
• Early Pregnancy EM Rounds Blog (St. John’s Regional Hospital, NB)
• Early Pregnancy Complications Podcast (emergencymedicinecases.com)
• POCUS for Vaginal Bleeding Blog (emergencymedicinecases.com)
• POCUS for 1^st trimester bleeding (ACEP)

ALiEM Cards

• Ectopic diagnosis
• 1^st trimester transabdominal ultrasound
• 1^st trimester transvaginal ultrasound
• Methotrexate

Patient Resources

• Ectopic Pregnancy Patient Information Sheet (PHC and VCH)
• Ectopic Pregnancy (familydoctor.org)

1. ACOG Practice Bulletin No. 193. Obstet Gynecol. 2018;131(3):e91-e103. 

   
   

2. Barash JH, Buchanan EM, Hillson C. Diagnosis and management of ectopic pregnancy. Am Fam Physician. 2014;90(1):34-40. Accessed December 2, 2019.

   
   

3. Hahn SA, Promes SB, Brown MD, et al. Clinical Policy: Critical Issues in the Initial Evaluation and Management of Patients Presenting to the Emergency Department in Early Pregnancy. Ann Emerg Med. 2017;69(2):241-250.e20. 

   
   

4. Huancahuari N. Emergencies in early pregnancy. Emerg Med Clin North Am. 2012;30(4):837-847. 

   
   

5. Promes SB, Nobay F. Pitfalls in first-trimester bleeding. Emerg Med Clin North Am. 2010;28(1):219-234, x. 

   
   

6. Stein JC, Wang R, Adler N, et al. Emergency Physician Ultrasonography for Evaluating Patients at Risk for Ectopic Pregnancy: A Meta-Analysis. Ann Emerg Med. 2010;56(6):674-683. 

   
   

7. Morin L, Cargill YM, Glanc P. Ultrasound Evaluation of First Trimester Complications of Pregnancy. J Obstet Gynaecol Canada. 2016;38(10):982-988. 

   
   

8. Kadar N, DeVore G, Romero R. Discriminatory hCG zone: its use in the sonographic evaluation for ectopic pregnancy. Obstet Gynecol. 1981;58(2):156-161. Accessed December 2, 2019.

   
   

9. Doubilet PM, Benson CB, Bourne T, Blaivas M. Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester. Campion EW, ed. N Engl J Med. 2013;369(15):1443-1451.