Many women are confused when told that they have a blighted ovum, which means there is not a fetus inside the pregnancy sac. With a blighted ovum you have been pregnant. The fact that your pregnancy hormonal levels (HCG) increased gave you a positive pregnancy test. No doubt, you became as excited as any woman would be about the idea of having a baby.
When you have an ultrasound scan, however, you will see only an empty sac because with a blighted ovum the fetus dose not develop. Normally, an egg, once fertilized, develops. Imagine then, the mass of developing cells going in two different directions. One to form the pregnancy sac and the other to form the embryo. In the case of a blighted ovum, the second stage just dose not happen: the pregnancy sac develops, but the embryo dose not. You can liken it to growing beans and waiting for the sprouts to shoot through. Some just do not take. Roots may develop but there are no stems.
Weeks may go by without your bleeding or starting to lose the pregnancy. After a while you may have a very dark brown discharge, and your breasts may stop feeling so swollen or sensitive. You probably won’t miscarry spontaneously for a long time. The blighted ovum may not be discovered until you visit your doctor and have an ultrasound scan to look for the fetal heartbeat.
We are diagnosing more blighted ova today. They are thought to be caused by a lack of chromosomes either from a poor sperm or a poor egg. And it affects older couples more often. One of the reason why we are seeing it so often is that we use ultrasound more often in early pregnancy and can therefore detect the empty sac. Also, as the age of parents becomes gradually older, there is an increased risk of a miscarriage from poor egg or sperm quality.
Fifteen years or so ago, any woman who went to her doctor because the pregnancy was not developing, or because she was bleeding, was often unable to be given a definite diagnosis. Now, fortunately, aw can tell more accurately what has happened by using sonography. But still we can do nothing to save a blighted ovum. With ultrasound, we are becoming more aware of various eventualities: for example, your doctor might be able to see three or four empty sacs inside the uterus. Some women may be conceiving blighted multiple ova. Women have hundreds of thousands of eggs, and men have millions of sperm, and it seems that more often than we realized, more than one egg is fertilized at the same time.
We are aware now of a “vanishing twin.” A twin pregnancy is diagnosed, then after some vaginal bleeding a repeat sonogram shows that one of the twins has disappeared (or miscarried) while the other continues to grow normally.
Just within the last year, ultrasound, as we mentioned earlier, has become more sophisticated. The transvaginal probe has been developed, which when inserted into the vagina right up against the uterus, can detect very pregnancies in some detail. This means we can diagnose a normal continuing pregnancy much earlier than was previously possible, and thus eliminate the diagnosis of a blighted ovum early on.