What is a blighted ovum?
Blighted ovum refers to a pregnancy in which the embryo did not develop or failed earlier than six-and-a-half weeks. When a sonogram is performed, only the gestational sac that would have surrounded the embryo is seen.
The vast majority of blighted ovum are caused by wrong chromosome number in the conceptus. This means that an error occurred when the egg or the sperm was dividing its genetic information in half in order to create the pregnancy. Occasionally blighted ovum are caused by a problem with the egg or sperm, so that too much genetic information from either the egg or the sperm is present in the pregnancy. Recently, early x-rays or early viruses have also been suggested as a possible cause.
Because the placenta can continue to grow and support itself without a baby for a short time, pregnancy hormone levels can continue to rise after the death of the embryo. However, they may not increase at the rate doctors look for to document a healthy pregnancy. (Doctors generally look for levels to approximately double every two or so days, although there is often some individual variation.)
The chance of a blighted ovum recurring are best assessed by your age since, the older you are, the higher the chance of a chromosomal abnormality.
