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Large yolk sac

A large yolk sac is one measuring >5-6 mm in pregnancies between a gestational age of 5-10 weeks. One study had shown that a yolk sac diameter of >5 mm can be associated with an increased risk of spontaneous miscarriage although few other authors have mentioned the existence of a very large yolk sac (e.g. around 8 mm) in a normal live pregnancy 2

Abnormally large yolk sac may indicate a poor obstetric outcome and close follow-up with sonography is often recommended for these pregnancies. 

Practical points 

  • indeterminate abnormal yolk sac abnormality that should not be considered alone for the diagnosis of failed early pregnancy 
  • follow-up ultrasonography at 7-14 days to assess the pregnancy for viability is generally appropriate
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Article information

rID: 46096
System: Obstetrics
Synonyms or Alternate Spellings:
  • Large yolk sac size
  • Large yolk sac diameter

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