Alternative Names
Abortion - spontaneous; Spontaneous abortion
Definition of Miscarriage:
A miscarriage is the spontaneous loss of a fetus before the 20th week of pregnancy. (Pregnancy losses after the 20th week are called preterm deliveries.)
A miscarriage may also be called a "spontaneous abortion." This refers to naturally occurring events, not elective or therapeutic abortion procedures, which a woman may choose to have done.
Other terms for the early loss of pregnancy include:
Causes, incidence, and risk factors:
Most miscarriages occur when the unborn baby has deadly genetic problems. Usually, these problems are unrelated to the mother.
Other possible causes for miscarriage include:
- Infection
- Physical problems in the mother
- Hormonal factors
- Immune responses
- Serious systemic diseases of the mother (such as diabetes or thyroid disease)
It is estimated that up to 50% of all fertilized eggs die and are lost (aborted) spontaneously, usually before the woman knows she is pregnant. Among known pregnancies, the rate of miscarriage is approximately 10% and usually occurs between the 7th and 12th weeks of pregnancy.
The risk for miscarriage is higher in women:
- Over age 35
- With certain diseases such as diabetes or thyroid problems
- With a history of three or more prior miscarriages
