Miscarriage Health Article

Definition

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:

• Missed abortion (a loss of pregnancy where the products of conception do not exit the body)
• Incomplete abortion (not all of the products of conception exit the body)
• Complete abortion (all of the products of conception exit the body)
• Threatened abortion (symptoms indicate a miscarriage is possible)
• Inevitable abortion (the symptoms cannot be stopped, and a miscarriage will happen)
• Infected abortion

Alternative Names

Abortion - spontaneous; Spontaneous abortion

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

Symptoms

Possible symptoms include:

• Low back pain or abdominal pain that is dull, sharp, or cramping
• Vaginal bleeding, with or without abdominal cramps
• Tissue or clot-like material that passes from the vagina

However, about 20% of pregnant women have some vaginal bleeding during the first 3 months of pregnancy. Approximately half of these women have a miscarriage.