Missed abortion (miscarriage)
What is missed abortion (miscarriage)?
This is a situation where the fetus or embryo ceases to be viable in the course of the pregnancy, but is retained in the womb. Again, there is little warning in many cases. Sometimes, the warning may come in the sudden disappearance of pregnancy symptoms.
If the pregnancy is advanced into the second trimester, some women may experience some light leakage of breast milk.
What causes missed abortion?
The cause is not clearly known. Chromosomal or genetic abnormalities are certainly to blame in some cases, but not all.
How does the hospital deal with a missed abortion?
It depends on the stage of the pregnancy. If it is early in the first trimester, evacuation of the uterus in theatre under a general anaesthetic is preferred. Again there is the option of medical management in the form of orally administered tablets typically followed by vaginal or rectal pessaries a couple of days later. This should normally trigger the passage of the products of conception. With this a procedure to clean out the womb in theatre may still be required.
Another alternative is to await spontaneous miscarriage to take place. This is not popular with gynaecologists because it has an inherent risk of causing clotting abnormalities, especially if the uterine contents are retained for several weeks (which is possible). Moreover, spontaneous miscarriage may take place and surgical evacuation of the uterus may still be necessary, if some products are retained and/or there is serious bleeding.
What are the direct consequences of missed abortion on future fertility?
What is molar pregnancy?
This is an abnormal form of pregnancy where, instead of a fetus, a mass of grape-like vesicles form and proliferate in the womb. The woman will feel pregnant as usual and pregnancy symptoms such as nausea and vomiting may be greatly exaggerated. The fundus may also be bigger than suggested by the dates. An ultrasound scan will immediately confirm the diagnosis.
This condition is discussed in greater detail in Chapter 17, "Cancer and Pregnancy".
Please note: Molar pregnancy is not a form of cancer. It is placed in that chapter for reasons that are explained there.
Spontaneous miscarriage is the most common form of early pregnancy loss. Do we know the causes?
This is a common problem but there is no common explanation to all of them. There is no doubt after extensive studies that chromosomal and genetic abnormalities account for a big proportion of spontaneous miscarriages. Some of these abnormalities are so severe that they are incompatible with life even in the womb, let alone outside.
Apart from chromosomal and genetic abnormalities, are there any other known causes of spontaneous miscarriage?
Yes. Abnormalities in the immune system of the mother could cause miscarriage, which could be a recurrent problem.
Abnormalities of the womb may be such that it is unable to carry a pregnancy beyond a certain time-span and this will cause early pregnancy loss.
Some infections, especially viral, may lead to miscarriage; and some diseases such as diabetes, if poorly controlled, may lead to early pregnancy failure.
Can you explain the immune system problem?
It is now well established that some women who suffer recurrent miscarriages have some abnormal antibodies, which may have a serious deleterious effect on the small blood vessels in the placenta, and therefore compromise the blood supply to the fetus. This may lead to miscarriage. In fact, the chances of miscarriage in an untreated individual is as high as 75-90 per cent. This condition is known as antiphospholipid syndrome.