Health Encyclopedia

Abortion - threatened

Definition

A threatened abortion is a condition that suggests a miscarriage might take place before the 20th week of pregnancy.

Alternative Names

Threatened miscarriage; Threatened spontaneous abortion

Causes, incidence, and risk factors

A small number of pregnant women have some vaginal bleeding, with or without abdominal cramps, during the first trimester of pregnancy. This is known as a threatened abortion. Most of these pregnancies go on to term with or without treatment. Spontaneous abortion occurs in just a small percentage of women who have vaginal bleeding during pregnancy.

When spontaneous abortion occurs, the usual cause is fetal death. Such death is typically the result of a chromosomal or developmental problem. Other possible causes include:

Defects in the mother's anatomy
Endocrine factors
Immune system factors
Infection
Systemic disease in the mother

About half of all fertilized eggs abort on their own, usually before the woman knows she is pregnant. The rate of spontaneous abortion is very low among known pregnancies. These usually occur 7 - 12 weeks into the pregnancy.

Risks of threatened abortion are higher in:

Women over age 35
Women with a history of 3 or more spontaneous abortions
Women with systemic disease (such as diabetes or thyroid dysfunction)

Symptoms

Abdominal cramps with or without vaginal bleeding
Vaginal bleeding during the first 20 weeks of pregnancy (last menstrual period was less than 20 weeks ago)

Note: With true miscarriage, low back pain or abdominal pain (dull to sharp, constant to intermittent) typically occurs and tissue or clot-like material may pass from the vagina.

Signs and tests

Pelvic exam shows a cervix that isn't thinned (effaced) or open (dilated). Either of these can suggest that a miscarriage will soon occur.

Other tests include:

Beta HCG (quantitative) test over a period of days or weeks to confirm whether the pregnancy is continuing or the fetus has died
CBC to find out the amount of blood loss
Serum HCG to confirm that the woman is pregnant
Ultrasound to detect fetal heartbeat
WBC with differential to rule out infection

This disease also can change the results of the serum progesterone test.

Treatment

Bed rest or pelvic rest (not having intercourse, douching, or using tampons) may be recommended, but there is no evidence to show that these actually reduce the miscarriage rate.

The use of progesterone is controversial. It might relax smooth muscles, including the muscles of the uterus. However, it also might increase the risk of an incomplete abortion or an abnormal pregnancy. Unless there is a luteal phase defect, progesterone should not be used.

Expectations (prognosis)

The outcome is good when the pregnancy continues to progress and all the symptoms disappear.

Complications

Anemia
Dead fetus syndrome
Infection
Moderate-to-heavy blood loss
Spontaneous abortion

Calling your health care provider

If you know you are (or are likely to be) pregnant and you have any symptoms of threatened abortion, contact your prenatal health care provider immediately.

Prevention

Some studies show that women who get prenatal care have better pregnancy outcomes, for themselves and their babies. Early and complete prenatal care reduces the risk of miscarriage.

It is better to find and treat health problems before you get pregnant than to wait until you're already pregnant. Avoiding environmental hazards such as x-rays and infectious diseases also decreases the risk of miscarriage in early pregnancy.

Spontaneous abortion is not preventable if the fetus dies. In fact, it is important for the uterus to expel all of its contents in such cases. A missed abortion occurs when a dead fetus is not expelled from the uterus. When only part of the dead fetus is expelled, it is called an incomplete abortion.

Review Date:8/17/2007
Reviewed By:Melanie N. Smith, M.D., Ph.D., Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Boston, MA. Review provided by VeriMed Healthcare Network.

ADAM Quality A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.