Blighted ovum

A blighted ovum, or anembryonic pregnancy occurs when a fertilized egg never develops an embryo after attaching itself to the uterine wall. The gestational sac, however, continues to develop until a spontaneous miscarriage occurs or a dilatation and curettage is done.

Signs and symptoms:

The usual signs of early pregnancy may be present (missed period, nausea, vomiting, etc.). A urine pregnancy test shows a positive result.

Diagnosis:

Transvaginal ultrasound (TVS) is usually requested to check for viability of an early pregnancy. There should be a gestational sac of adequate size (mean diameter of 13 mm and above) but with no visible yolk sac and embyonic pole on TVS in order to make a diagnosis of a blighted ovum.

It must be noted that a very early pregnancy with a small gestational sac (less than 13 mm diameter) may not show visible signs of either a yolk sac or embryonic pole yet, therefore a diagnosis of blighted ovum cannot be made yet. Repeat TVS should show an enlarging gestational sac and appearance of yolk sac and embryonic pole when the gestational sac is large enough in order to judge for viability of the pregnancy.

Causes:

Majority of blighted ova occur because of the presence of chromosomal abnormalities.

Treatment:

In some cases, the blighted ovum may spontaneously be aborted. However, some doctors and patients would prefer a D&C for physical and psychological closure.