Anembryonic pregnancy (blighted ovum, empty sac) may be associated with a number of findings on ultrasonography.


Findings on ultrasonography may include:

(1) gestational sac > 13 mm in diameter AND no yolk sac

(2) gestation sac > 18 mm in diameter AND no embryonic pole

(3) an empty gestational sac > 38 days gestation

(4) gestational sac volume much less than normal after 7 weeks (49 days) of gestation (Odeh et al)

(5) deformed (irregular) yolk sac (Cho et al)


There should be no interval growth in the gestational sac over 1 week.


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