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Miscarriage

(Spontaneous Abortion)

Definition

Miscarriage refers to the premature end of a pregnancy before the developing baby is able to survive outside the womb. Miscarriage can occur during the first or second trimester, before 20 weeks. Most occur in the first 12 weeks of pregnancy. They often are unexpected and isolated events. About 15%-20% of recognized pregnancies end this way.
Fetus in First Trimester
Nucleus image
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Causes

Miscarriages often occur for the following reasons:
  • Chromosomal abnormalities (common cause)
  • Abnormalities in the uterine tract (eg, fibroids)
  • Hormonal problems (eg, not having enough progesterone, a female hormone needed to support pregnancy)
  • Factors related to the immune system (eg, may cause blood-clotting problems or rejection of the fetus)
  • Trauma
In some cases, the cause is unknown.

Risk Factors

Factors that may increase the risk of miscarriage include:
  • Having an infection
  • Being older (maternal age of 35 years or older)
  • Smoking, drinking alcohol, or using drugs
  • Taking certain prescribed medicines
  • Being exposed to certain environmental toxins
  • Having a long-term condition that affects the immune system (eg, lupus, diabetes)
  • Having high-dose radiation therapy on the ovary and uterus or the pituitary gland during treatment for childhood cancer
Having a miscarriage during your first pregnancy may place you at a higher risk for complications during your next pregnancy. These complications may include:

Symptoms

Symptoms include some or all of the following:
  • Vaginal bleeding
  • Pink or brown discharge
  • Cramping
  • Passing the fetus, placenta, and surrounding membranes through the vagina
  • Fever

Recurrent Miscarriage

While miscarriage usually is a one-time occurrence, up to 1 in 20 couples experience two miscarriages in a row, and 1 in 100 have three or more. In some cases, these couples have an underlying problem. Couples who have experienced two or more miscarriages should have a complete medical evaluation to learn the cause and how they can prevent another one from occurring.
Testing can reveal the cause of repeat miscarriages in at least 75% of couples.
  • Chromosome problem in one member of the couple in 5%
  • Uterine abnormalities in 10%-15%
  • Hormone problems in 5%-40%
  • Immune system problems in 5%-10%
  • Unknown causes in 25%

Diagnosis

You will be asked about your symptoms, the length of your pregnancy, and when you first noticed a change in your condition. The doctor will perform physical and pelvic exams.
Prior to miscarriage, tests may include:
  • Ultrasound testing—to assess the health of the fetus or detect an ectopic pregnancy (a pregnancy in which development occurs outside the uterus)
  • Blood test—to check the exact amount of the hormone (called human chorionic gonadotropin or hCG) important to sustain an early pregnancy
After miscarriage, tests may include:
  • Examination of the tissue that has passed through the vagina
  • Blood tests—to check for a chromosomal error in the man or the woman or to check hormone and antibody levels
  • Imaging tests—(eg, x-rays, ultrasound) to identify a problem with your uterus
  • Endometrial biopsy—to check the uterine lining to see if it can support a pregnancy
  • Hysteroscopy—to examine the inside of the uterus

Treatment

Immediate care usually involves observation only, especially in early or first trimester miscarriages. Medicine may be indicated in the event of heavy bleeding or cramping. A dilation and evacuation (D&E) may be needed if uterine contents are not spontaneously expelled (passed through the vagina). During a D&E, the doctor dilates the cervix, inserts a tool into the uterus, and suctions out remaining material.

Medications

Medicines to decrease the chance of miscarriage may include:
  • Antibiotics for infection
  • Hormone (progesterone) supplements
  • Aspirin and other medicines to treat blood-clotting problems

Surgery

Some uterine problems can be corrected to prevent another miscarriage. Examples include:
  • Uterine fibroids
  • Septate uterus (tissue in the center of the uterus)
  • Incompetent (weakened) cervix

Support Services

To help you deal with your loss, the doctor can refer you to a mental health therapist. You may also benefit from participating in a support group.

Prevention

Before you start to plan your next pregnancy consider the following regarding your health:
  • Is your diet ready to support another pregnancy?
  • Are there habits you should change prior to another pregnancy?
  • What medicines are you taking and will they affect a pregnancy?
  • How is your health?
  • Are there issues you should resolve before trying another pregnancy?

RESOURCES

The American College of Obstetricians and Gynecologists http://www.acog.org/

The International Council on Infertility Information Dissemination http://www.inciid.org/

March of Dimes Foundation http://www.marchofdimes.com/

CANADIAN RESOURCES

The Society of Obstetricians and Gynaecologists of Canada http://www.sogc.org/

Women's Health Matters http://www.womenshealthmatters.ca/

References

Miscarriage. American Pregnancy Association website. Available at: http://www.americanpregnancy.org/pregnancycomplications/miscarriage.html/. Updated November 2011. Accessed August 10, 2012.

Miscarriage. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/. Updated August 3, 2012. Accessed August 10, 2012.

Miscarriage. March of Dimes website. Available at: http://www.marchofdimes.com/baby/loss%5Fmiscarriage.html. Updated October 2008. Accessed August 10, 2012.

12/2/2008 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php: Winther JF, Boice JD Jr, Svendsen AL, Frederiksen K, Stovall M, Olsen JH. Spontaneous abortion in a Danish population-based cohort of childhood cancer survivors. J Clin Oncol. 2008;26:4340-4346.

4/16/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php: Bhattacharya S, Townend J, Shetty A, Campbell D, Bhattacharya S. Does miscarriage in an initial pregnancy lead to adverse obstetric and perinatal outcomes in the next continuing pregnancy? BJOG. 2008;115:1623-1629.

6/25/2010 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php: Nakhai-Pour HR, Broy P, Bérard A. Use of antidepressants during pregnancy and the risk of spontaneous abortion. CMAJ. 2010 May 31.

Revision Information

  • Reviewer: Andrea Chisholm
  • Review Date: 09/2012 -
  • Update Date: 00/91/2012 -

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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