Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention
Miscarriage means loss of an embryo or fetus before the 20th week of pregnancy. Most miscarriages occur during the first 14 weeks of pregnancy. The medical term for miscarriage is spontaneous abortion.
Miscarriages are very common. Approximately 20% of pregnancies (one in five) end in miscarriage. The most common cause is a genetic abnormality of the fetus. Not all women realize that they are miscarrying and others may not seek medical care when it occurs.
A miscarriage is often a traumatic event for both partners, and can cause feelings similar to the loss of a child or other member of the family. Fortunately, 90% of women who have had one miscarriage subsequently have a normal pregnancy and healthy baby; 60% are able to have a healthy baby after two miscarriages. Even a woman who has had three miscarriages in a row still has more than a 50% chance of having a successful pregnancy the fourth time.
Causes and symptoms
There are many reasons why a woman's pregnancy ends in miscarriage. Often the cause is not clear. However, more than half the miscarriages that occur in the first eight weeks of pregnancy involve serious chromosomal abnormalities or birth defects that would make it impossible for the baby to survive. These are different from inherited genetic diseases. They probably occur during development of the specific egg or sperm, and therefore are not likely to occur again.
In about 17% of cases, miscarriage is caused by an abnormal hormonal imbalance that interferes with the ability of the uterus to support the growing embryo. This is known as luteal phase defect. In another 10% of cases, there is a problem with the structure of the uterus or cervix. This can especially occur in women whose mothers used diethylstilbestrol (DES) when pregnant with them.
The risk of miscarriage is increased by:
- smoking (up to a 50% increased risk)
- exposure to toxins (such as arsenic, lead, formaldehyde, benzene, and ethylene oxide)
- multiple pregnancies
- poorly-controlled diabetes
The most common symptom of miscarriage is bleeding from the vagina, which may be light or heavy. However, bleeding during early pregnancy is common and is not always serious. Many women have slight vaginal bleeding after the egg implants in the uterus (about 7-10 days after conception), which can be mistaken for a threatened miscarriage. A few women bleed at the time of their monthly periods through the pregnancy. However, any bleeding in the first three months of pregnancy (first trimester) is considered a threat of miscarriage.
Women should not ignore vaginal bleeding during early pregnancy. In addition to signaling a threatened miscarriage, it could also indicate a potentially life-threatening condition known as ectopic pregnancy. In an ectopic pregnancy, the fetus implants at a site other than the inside of the uterus. Most often this occurs in the fallopian tube.
Cramping is another common sign of a possible miscarriage. The cramping occurs because the uterus attempts to push out the pregnancy tissue. If a pregnant woman experiences both bleeding and cramping the possibility of miscarriage is more likely than if only one of these symptoms is present.
If a woman experiences any sign of impending miscarriage, she should be examined by a practitioner. The doctor or nurse will perform a pelvic exam to check if the cervix is closed as it should be. If the cervix is open, miscarriage is inevitable and nothing can preserve the pregnancy. Symptoms of an inevitable miscarriage may include dull relentless or sharp intermittent pain in the lower abdomen or back. Bleeding may be heavy. Clotted material and tissue (the placenta and embryo) may pass from the vagina.
A situation in which only some of the products in the uterus have been expelled is called an incomplete miscarriage. Pain and bleeding may continue and become severe. An incomplete miscarriage requires medical attention.
A "missed abortion" occurs when the fetus has died but neither the fetus nor placenta is expelled. There may not be any bleeding or pain, but the symptoms of pregnancy will disappear. The physician may suspect a missed abortion if the uterus does not continue to grow. The physician will diagnose a missed abortion with an ultrasound examination.
A woman should contact her doctor if she experiences any of the following:
- any bleeding during pregnancy
- pain or cramps during pregnancy
- passing of tissue
- fever and chills during or after miscarriage
If a woman experiences any sign of impending miscarriage she should see a doctor or nurse for a pelvic examination to check if the cervix is closed, as it should be. If the cervix is open, miscarriage is inevitable.
An ultrasound examination can confirm a missed abortion if the uterus has shrunk and the patient has had continual spotting with no other symptoms.
For women who experience bleeding and cramping, bed rest is often ordered until symptoms disappear. Women should not have sex until the outcome of the threatened miscarriage is determined. If bleeding and cramping are severe, women should drink fluids only.
Although it may be psychologically difficult, if a woman has a miscarriage at home she should try to collect any material she passes in a clean container for analysis in a laboratory. This may help determine why the miscarriage occurred.
An incomplete miscarriage or missed abortion may require the removal of the fetus and placenta by a D&C (dilatation and curettage). In this procedure the contents of the uterus are scraped out. It is performed in the doctor's office or hospital.
After miscarriage, a doctor may prescribe rest or antibiotics for infection. There will be some bleeding from the vagina for several days to two weeks after miscarriage. To give the cervix time to close and avoid possible infection, women should not use tampons or have sex for at least two weeks. Couples should wait for one to three normal menstrual cycles before trying to get pregnant again.
A miscarriage that is properly treated is not life-threatening, and usually does not affect a woman's ability to deliver a healthy baby in the future.
Feelings of grief and loss after a miscarriage are common. In fact, some women who experience a miscarriage suffer from major depression during the six months after the loss. This is especially true for women who don't have any children or who have had depression in the past. The emotional crisis can be similar to that of a woman whose baby has died after birth.
The majority of miscarriages cannot be prevented because they are caused by severe genetic problems determined at conception. Some doctors advise women who have a threatened miscarriage to rest in bed for a day and avoid sex for a few weeks after the bleeding stops. Other experts believe that a healthy woman (especially early in the pregnancy) should continue normal activities instead of protecting a pregnancy that may end in miscarriage later on, causing even more profound distress.
If miscarriage was caused by a hormonal imbalance (luteal phase defect), this can be treated with a hormone called progesterone to help prevent subsequent miscarriages. If structural problems have led to repeated miscarriage, there are some possible procedures to treat these problems. Other possible ways to prevent miscarriage are to treat genital infections, eat a well-balanced diet, and refrain from smoking and using recreational drugs.
Allen, Marie, and Shelly Marks. Miscarriage: Women Sharing From the Heart. New York: John Wiley & Sons, 1993.
Friedman, Lynn, Irene Daria, and Laurie Abkemeier. A Woman Doctor's Guide to Miscarriage. New York: Hyperion, 1996.
Hinton, Clara H. Silent Grief; Miscarriage—Finding Your Way Through the Darkness. Green Forest, AK: New Leaf Press, 1998.
Ingram, Kristen J., and Christine O. Lafser. Always Precious in our Memory: Reflections After Miscarriage, Stillbirth, or Neonatal Death. Anaheim, CA: Acta Publications, 1997.
Lachelin, Gillian C. L. Miscarriage: The Facts. New York: Oxford Medical Publications, 1996.
Vredevelt, Pam W. Empty Arms: Emotional Support for Those Who Have Suffered Miscarriage or Stillbirth. New York: Questar Publications, 1995.
"Aftermath of Loss." U.S. News and World Report 122, no. 6 (17 Feb. 1997): 66.
Bennetts, L. "Preventing Miscarriage." Parents, Feb. 1994, 64-66.
Petterson, S. "Miscarriage Myths." Your Health, 25 Jan. 1994, 23-24.
American College of Obstetricians and Gynecologists. 409 12th Street, S.W., P.O. Box 96920
Hygeia Foundation, Inc. P.O. Box 3943 New Haven, CT 06525. (203) 387-3589. <http://www.hygeia.org>.
Carol A. Turkington
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