Large yolk sac

Last revised by Jeremy Jones on 20 Sep 2021

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

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.