After bleeding and cramping, many women heave a sigh of relief when the doctor tells them they’ve had a “missed miscarriage”. While the words may mean that the woman has missed the miscarriage, it actually has a very different definition.
A missed miscarriage is when the fetus in a woman’s womb dies, but the pregnancy continues. In short, unlike the classic miscarriage (wherein a woman bleeds and passes tissues and clots), this type of spontaneous abortion does not cause the fetus to be expelled from the mother’s body. Not knowing she has miscarried can cause more complications once the fetus is left dead in the uterus. Unfortunately, some women are not aware at all until ultrasound and Doppler exams have been performed by her doctor to reveal a non-moving, non-breathing fetus. This type of miscarriage is also called “silent pregnancy” or “missed abortion”. Most cases occur within the first trimester, or twelve weeks of pregnancy. If this type of miscarriage occurs past the first trimester, it is given the name late missed miscarriage.
A woman may experience a sudden decrease in her typical pregnancy signs. For instance, she may not feel nauseous anymore, or her breasts may feel less sore. A missed miscarriage is different because brownish vaginal discharge precedes the bright red bleeding. Tests such as a Doppler exam (to listen for heartbeat) and an ultrasound (to view the baby) are done routinely during prenatal checkups, and this may be the only time a woman finds out she has silently miscarried.
Once the diagnosis has been made, the mother is immediately scheduled for an emergency D&C (dilatation and curettage). The doctor dilates the cervix and with the use of a surgical instrument that’s shaped like a spoon, scrapes the contents of the uterus to empty it. This is crucial in order to prevent infection that may lead to sepsis, or worse, death of the mother. After the treatment, a woman must be given psychological support for her loss.
Source; http://www.pregnancywizard.com