Definition of Blighted ovum

Blighted ovum: A fertilized ovum (egg) that did not develop or whose development ceased at an early stage, before 6 or 7 weeks of gestation. On the ultrasound examination of a blighted ovum, only the gestational sac that normally surrounds the embryo can be seen. There is usually no embryo inside the gestational sac.

A blighted ovum is a form of early spontaneous abortion (miscarriage). At least 50% of early spontaneous abortions are due to chromosome abnormalities. The most common chromosome abnormalities in early spontaneous abortions are 47, +16 (an extra chromosome #16) and 45, X (a missing X or Y chromosome). These two chromosome abnormalities are not familial and do not recur in future pregnancies.