Viable pregnancy defined as one with potential for live birth

Nonviable pregnancy is one that will not result in live birth

Probable intrauterine pregnancy (IUP)

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  Intrauterine sac-like structure without yolk sac (YS) or embryo

Definite IUP

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  Intrauterine sac-like structure with YS or embryo (± cardiac activity)

Intrauterine pregnancy of uncertain viability

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  Definite IUP that does not meet criteria to be called nonviable

Criteria for nonviable pregnancy on vaginal US

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  Mean sac diameter > 25 mm without embryo

  
  
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  Crown rump length ≥ 7 mm without cardiac activity

  
  
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  Cessation of previously documented cardiac activity

Time follow-up intervals to allow for definitive diagnosis of nonviable pregnancy

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  Lack of live embryo 11 days after demonstration of gestational sac with YS is diagnostic

  
  
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  Lack of live embryo 14 days after demonstration of gestational sac without YS is diagnostic

Published signs of failed pregnancy not included in 2013 consensus panel statement

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  Empty amnion sign

  
  
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  Expanded amnion sign

  
  
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  Yolk stalk sign

Use vaginal US for highest resolution images

With positive pregnancy test

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  Intrauterine sac-like structure with rounded edges is statistically IUP

  
  
  
  
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    Probable IUP if no YS or embryo

    
    
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    Definite IUP if YS or embryo visible

  
  
  
  
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  Intrauterine sac-like structure with pointed edges concerning for nonviable IUP or blood products in setting of ectopic

  
  
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  Empty uterus + normal adnexa → pregnancy of unknown location

  
  
  
  
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    Must follow these patients with serial β-hCG as 10-20% have ectopic pregnancy