The term missed miscarriage refers to a pregnancy loss in which the baby has stopped developing, and the pregnancy is no longer viable, but the woman is not yet having clear miscarriage symptoms.
In a missed miscarriage, usually a doctor discovers the condition during a routine prenatal checkup. For example, in a woman without vaginal bleeding or cramping, two consecutive hCG blood tests could show that the level of hCG in a woman's blood is decreasing or an ultrasound could reveal that a baby's heartbeat has stopped. Sometimes the first clue of a missed miscarriage is that the baby's heartbeat fails to become audible on a fetal heart rate monitor by 12 weeks of gestation.
After a missed miscarriage diagnosis, a woman often faces a choice of whether or not to seek intervention for the miscarriage. If bleeding has not yet started, a natural miscarriage, (a.k.a. a miscarriage without intervention) might take days or weeks to begin. Many women with this diagnosis opt for a D & C in order to have the ordeal over with as quickly as possible.
Some missed miscarriages are due to a condition called blighted ovum. In a blighted ovum, the gestational sac and placenta continue to develop but the baby does not. A woman might continue to experience pregnancy symptoms, but then the baby's heartbeat never becomes audible on a heart rate monitor and an ultrasound ultimately reveals an empty gestational sac.
Like most first-trimester miscarriages, the usual cause of missed miscarriages is chromosomal abnormalities in the developing baby. These are random in nature and the woman's next pregnancy has a reasonable chance of being normal. Women with recurrent miscarriages should talk to a doctor about testing for possible recurrent miscarriage causes outside of chromosomal abnormalities.
Source:
American Pregnancy Association, "Miscarriage." July 2007. Accessed 10 Jan 2008.
