Spontaneous abortion, or miscarriage, is the loss of a fetus before 20 weeks
of pregnancy. The most common cause of miscarriage is a genetic abnormality.
About one-third to one-half of all pregnancies result in miscarriage. A second
miscarriage generally occurs in only 1% of women. However, there are women who
experience habitual miscarriages (three or more consecutive spontaneous
abortions). Almost one-third of miscarriages may occur as a late menstrual
period, even before a woman knows for certain that she is pregnant.
Signs and Symptoms
Miscarriage is often accompanied by the following signs and
Bleeding—brown or bright red vaginal bleeding
Passage of clots or a gush of clear or pink vaginal fluid (may
indicate pregnancy tissue from the uterus)
Abdominal pain or cramping
Decrease in signs of pregnancy, such as breast sensitivity and morning
Dizziness, lightheadedness, or feeling
What Causes It?
A wide range of health conditions that affect at least one parent can cause a
miscarriage, including the following:
Chromosomal abnormalities account for up to 60% of losses
Physical problems, such as distortion of the uterine cavity or
adhesions from disease or surgery
Endocrine or hormone disorders, such as diabetes (when poorly
controlled) and hyper- or hypothyroidism
Infection, including bacterial, viral, parasitic, fungal, or acquired
through sexually transmitted diseases
Abnormal antibodies in the blood that cause formation of blood clots
(for example, antiphospholipid antibodies, or APLA)
Other factors of conception (such as defective sperm cells, time of
egg implantation), or stress
Who's Most At Risk?
People with the following conditions or characteristics are at risk for
having a miscarriage:
Previous spontaneous abortion
Women age 35 or older
Cigarette smoking—smoking half a pack or more
per day significantly increases risk
Alcohol—risk doubles with more than two
drinks per day
Caffeine—see section on Nutrition for
Environmental toxins—excessive exposure to
lead, mercury, organic solvents
Serious maternal illness
Flight attendants working more than 74 hours per month
Maternal or paternal handling of anti-cancer agents
Increased levels of homocysteine (see Nutrition
What to Expect at Your Provider's Office
If you think you are having a miscarriage, see your healthcare provider. He
or she will take a comprehensive medical, family, and social history to try to
determine if there is a suggestion of an underlying cause. A pelvic examination
detects uterine abnormalities. Ultrasound imaging and other diagnostic and
laboratory tests may be used to confirm diagnosis and to evaluate the condition
of the uterus and fetus.
Avoiding known risks, such as caffeine, alcohol, and cigarette smoking, as
well as other risks listed above may help prevent miscarriage.
Immediate treatment sometimes involves surgery to remove pregnancy tissue.
Your healthcare provider may recommend counseling to help you through the
grieving process. In vitro fertilization, embryo transfer, or artificial
insemination may be used to achieve a successful pregnancy if you have a history
of unexplained, recurrent miscarriages.
Your healthcare provider may prescribe the following medications to treat
underlying conditions or, in the case of repeated miscarriages, to help you
achieve a successful pregnancy:
Antibiotics to treat infections
Estrogen supplementation following uterine surgery for adhesions to
stimulate the growth of the uterine lining
Aspirin followed by heparin if a clotting abnormality is
Vaginal progesterone suppositories
Surgical and Other Procedures
Dilation and curettage (D&C) may be performed to remove pregnancy tissue
if it has not been expelled naturally from the uterus. Other surgical procedures
may be performed to address uterine problems or adhesions.
Complementary and Alternative Therapies
As indicated in the section, Who's Most At Risk,there appears
to be a strong connection between diet, lifestyle, and risk of spontaneous
abortion. Before becoming pregnant, therefore, it is a good idea to have
counseling about the risks, including the importance of avoiding caffeine,
alcohol, and recreational drugs. Also, some case reports suggest Chinese herbal
medicines may help prevent recurring miscarriages caused by immune system
problems. However, there is no clear scientific evidence of this.
Vitamin B Complex, Including Folic Acid:
Many naturopathic and other doctors suggest using vitamin B complex (50 mg a
day) with additional vitamin B6 and folic acid (800 to 1000 mcg a
day) for women planning to become pregnant and for those who are pregnant. These
preventive measures are supported by studies that suggest a connection between
recurring miscarriages and problems metabolizing methionine and homocysteine in
the body. Methionine is an amino acid, a building block of protein. Homocysteine
is a by-product of the breakdown of methionine. Abnormal use of homocysteine by
the body leads to a rise in levels of this compound which, in turn, may play a
role in spontaneous abortion and the development of defects in the neural tube
(the structure in the fetus that later becomes the central nervous system).
Folic acid, vitamins B6 and B12, and betaine all play a
role in the proper use of methionine and homocysteine.
In addition, a fetus, a newborn, and a pregnant woman all need more folic
acid and B12 than other people; therefore, taking the supplements
mentioned both before and during pregnancy is valuable, and may prevent
miscarriage in the case of elevated homocysteine levels. Moderate to high
caffeine intake may also be related to elevated homocysteine levels.
Some substances—including caffeine and
pesticides—easily cross the placenta from the woman's
body to her fetus. Their impact on pregnancy is not entirely understood.
Caffeine stays in a pregnant woman's body much longer than in non-pregnant
healthy adults. It stays in newborns even longer. A study of 3135 pregnant women
showed that moderate-to-heavy caffeine users (those who had at least 151 mg
daily) were more likely to have late first- or second-trimester spontaneous
abortions compared with nonusers or light users. Light caffeine use (1 to 150 mg
daily) increased risk for abortion only in women who had a history of previous
spontaneous abortion. (One cup of coffee has 107 mg of caffeine, one cup of tea
has 34 mg, and one glass of cola has 47 mg, assuming all are caffeinated
beverages.) Coffee was the main source of caffeine in moderate-to-heavy users.
Light users were more likely to get caffeine from tea and other sources.
In addition, as mentioned in the subsection, Vitamin B Complex, Including
Folic Acid,researchers have recently reported that higher caffeine
intake may be related to higher levels of homocysteine. This may contribute to
the increased risk of spontaneous abortion in moderate coffee drinkers, but
further research is needed.
Studies suggest that coenzyme Q10 levels are lower in women who have had a
recent miscarriage. Similar to methionine and homocysteine described above, the
production of coenzyme Q10 in the body also depends on folic acid, vitamin
B12, and betaine. Therefore, the same supplements that support
methionine metabolism (namely, folic acid, vitamin B12, and betaine)
maintain normal coenzyme Q10 levels in the body.
Magnesium and Selenium:
A small study of infertile women and women with a history of miscarriage
suggests that low levels of magnesium may impair reproductive function, and may
contribute to miscarriage. Oxidation, a process that is damaging to cell
membranes, can lead to loss of magnesium. The same study suggests that the
antioxidant selenium protects the cell membrane, thereby maintaining appropriate
levels of magnesium. The authors of the study suggest taking both magnesium and
Women who have miscarried have lower levels of selenium than women who carry
a pregnancy to full term. Although the authors of the above-mentioned study do
not specify the exact amount to take, the recommended doses are generally 300 to
400 mg per day of magnesium and 200 mcg per day of selenium. Check the dosage in
your prenatal vitamin and discuss appropriate nutrient supplementation with your
Vitamin A, vitamin E, and beta-carotene levels tend to be lower in women who
have miscarried as well; these nutrients are generally found in prenatal
vitamins. Discuss the pros and cons of their use with your healthcare provider
before becoming pregnant or if you are already pregnant.
Eating fish contaminated with pollutants, namely persistent organochlorine
compounds (POCs), may increase pregnancy risk, although it is not clear whether
eating contaminated fish contributes to spontaneous
Western herbs may help clear up underlying endocrine problems. They may also
help reduce stress, but these have not yet been studied in relation to
spontaneous abortion specifically.
A Chinese and Japanese Herbal Remedy:
There are case reports of recurring spontaneous abortion caused by immune
system problems that have been successfully treated with Traditional Chinese
Medicine (TCM). Researchers gave Chinese herbs to 12 women, all of whom had had
at least two first-trimester miscarriages related to immune function
abnormalities. When their immune systems returned to normal as a result of
taking this preparation, the women were able to carry their pregnancies to term.
If you would like to consider working with an experienced traditional Chinese
physician, discuss this possibility with your gynecologist.
No scientific literature supports the use of homeopathy to prevent
spontaneous abortion. An experienced homeopath would consider your individual
case and may recommend treatments to address your underlying condition
andsupport your overall health.
No scientific literature supports the use of acupuncture to prevent
spontaneous abortion. However, many acupuncturists report success in treating
women with a history of spontaneous abortion, leading to the ability to carry
the pregnancy to full term. This may result from clearing up underlying
endocrine problems and reducing stress.
There is only a 1% chance of recurring miscarriage; however, the risk
increases significantly with each subsequent loss. Possible complications from
spontaneous abortion include infected pregnancy tissue, which could lead to
pelvic abscess, septic shock, or even death. Depression and guilt are common
feelings that may follow a miscarriage; as mentioned earlier, there are times
when counseling is appropriate.
Your healthcare provider will monitor you until the miscarriage is complete.
If you have suffered a miscarriage, you should see your provider very soon after
any future pregnancies.
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Review Date: October 2000
Reviewed By: Participants in the review process include: Shiva Barton, ND, Wellspace,
Cambridge, MA; Jacqueline A. Hart, MD, Department of Internal Medicine,
Newton-Wellesley Hospital, Harvard University and Senior Medical Editor
Integrative Medicine, Boston, MA; Leonard Wisneski, MD, FACP, George Washington
University, Rockville, MD.
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