Miscarriage is a lay term for pregnancy loss. In medical terms, early miscarriage is usually referred to using the following terms:
The following are the most common known factors in miscarriage:
According to the American Society for Reproductive Medicine, the usual cause of early miscarriage is aneuploidy. This is an abnormality in the number of chromosomes (such as missing or duplicated chromosomes). Up to 60% of all miscarriages are thought to be the result of random chromosomal abnormality. The reason for most of these errors is not known. Women over the age of 40 are more likely to lose an embryo due to chromosomal abnormalities. In fewer than 5% of cases, a genetic abnormality in the chromosomes of one of the parents is found to be the cause.
Congenital malformation or acquired abnormalities in the uterus are found to be the cause of recurring miscarriage in about 10-15% of patients. Uterine septum (a congenital condition in which the interior of the uterus is divided by a partition of tissue) is a well known factor in miscarriage. Polyps and fibroids that may form later in life can also contribute to miscarriage. When an embryo implants on an abnormal surface, it cannot obtain adequate nutrition or establish blood flow.
Hormonal, metabolic, and autoimmune disorders may also play a role in recurring miscarriage. These conditions include: