A blighted ovum is a fertilized egg that has ceased development at a very early stage.
On ultrasound examination there is a gestational sac (2.5 cc or more) in which no fetal pole can be identified.
Because the egg's supporting tissue (trophoblast) may continue to function for some time after the death of the embryo the sac may reach considerable size.
A blighted ovum is an example of a spontaneous abortion. Spontaneous abortion occurs in 15% of human pregnancies with most occurring during the first trimester.
More than half of spontaneous abortions have abnormal chromosomes .
Although small studies suggest that enzyme deficiencies in placental tissues , or abnormal expression of genes on particular chromosomes may be responsible for some cases of blighted-ovum abortion  the causes of a blighted ovum are likely to be similar to the causes of spontaneous abortion in general.
SEE ALSO : BLIGHTED OVUM
1. Boue J, Bou A, Lazar P.Retrospective and prospective epidemiological studies of 1500 karyotyped spontaneous human abortions.
Teratology. 12:11, 1975
2.Edlow JB, Huddleston JF, Lee G, Peterson WF, Robinson JC. Multiple enzyme deficiencies in placental tissue from two blighted-ovum abortions. Am J Obstet Gynecol. 111:36, 1971
3. Minelli E, Buchi C, Granata P, Meroni E, Righi R, Portentoso P, Giudici A,Ercoli A, Sartor MG, Rossi A, et al. Cytogenetic findings in echographically defined blighted ovum abortions.Ann Genet. ;36:107, 1993