What
is a miscarriage?
A miscarriage is the spontaneous
loss of a pregnancy
from conception to 20 weeks' gestation. The term stillbirth refers to the death
of a fetus after 20 weeks' gestation. Miscarriage is sometimes referred to as
spontaneous abortion, because the medical term abortion means the ending of a
pregnancy, whether intentional or unintentional. Most miscarriages occur in the
first trimester of pregnancy, between the 7th and 12th weeks of pregnancy.
How common is miscarriage?
Miscarriage is very common. Because
many or even most miscarriages occur so early in pregnancy that a woman might
not have known that she was pregnant, it is difficult to estimate how many miscarriages
occur. Some experts believe that about half of all fertilized eggs die before
implantation or are miscarried. Of known pregnancies (in which a woman misses a
period or has a positive pregnancy test), about 10% to 20% end in miscarriage.
The majority of miscarriages are
believed to be caused by genetic problems in the embryo that would prevent a
baby from developing normally and surviving. These fatal genetic errors
typically are not related to genetic problems in the mother.
In other cases, certain illnesses or
medical conditions can cause miscarriage and may increase the risk of
miscarriage. Mothers who have diabetes or thyroid disease are at increased risk of miscarriage.
Infections that spread to the placenta, including some viral infections, can
also increase the risk of miscarriage.
In general, risk factors for
miscarriage include the following:
- Older maternal age
- Cigarette smoking
(>10 cigarettes/day)
- Moderate to high alcohol consumption
- Trauma to the uterus
- Radiation exposure
- Previous miscarriage
- Maternal weight extremes (BMI either below 18.5 or
above 25 kg/m2)
- Anatomical abnormalities of the uterus
- Illicit drug use
- Use of non-steroidal anti-inflammatory drugs (NSAIDs)
around the time of conception may increase the risk of miscarriage
Women who had one miscarriage have
an incidence of miscarriage of about 20%, whereas women who have three or more
consecutive miscarriages may have a risk as high as 43%
What
are the types of miscarriage?
Miscarriages are sometimes referred
to by specific names to reflect the clinical findings or the type of
miscarriage. Examples include:
- Threatened abortion:
a woman may experience vaginal bleeding or others signs of miscarriage
(see below), but miscarriage has not occurred
- Incomplete abortion:
some of the products of conception (fetal and placental tissues) have been
expelled from the uterus, but some remain within the uterus
- Complete abortion:
all of the tissue from the pregnancy has been expelled
- Missed abortion:
the fetus has not developed, so there is no viable pregnancy, but there is
placental tissue contained within the uterus
- Septic abortion: a
miscarriage in which there is infection in the fetal and pregnancy
material before or after a miscarriage
What
are signs and symptoms of a miscarriage?
Vaginal bleeding and pelvic pain are
the hallmark symptoms of miscarriage. All vaginal bleeding during pregnancy
should be investigated, although not all instances of bleeding result from a
miscarriage. Bleeding in the first trimester of pregnancy is very common and
does not typically signify a miscarriage. The pain tends to be dull and
cramping, and it may come and go or be present constantly. Sometimes, there is
passage of fetal or placental tissue. This material may appear whitish and
covered with blood. Blood clots may also be present in the vaginal
bleeding. The degree of bleeding does not necessarily correlate with the
severity of the situation, and miscarriage may be associated with bleeding that
ranges from mild to severe.
How is miscarriage diagnosed?
An
ultrasound examination is typically performed if a
woman has symptoms of a miscarriage. The ultrasound can determine if the
pregnancy is intact and if a fetal heartbeat is present. Ultrasound examination
can also reveal whether the pregnancy is an
ectopic pregnancy (located outside of the uterus,
typically in the Fallopian tube), which may have similar symptoms and signs as
miscarriage. Other tests that may be performed include blood tests for
pregnancy hormones, blood counts to determine the degree of blood loss or to
see whether infection is present, and a
pelvic examination. The mother's blood type will also
be checked at the time of a miscarriage, so that Rh-negative women can receive
an injection of rho-D immune globulin (RhoGam) to prevent problems in future
pregnancies.
What happens after a miscarriage?
There are no specific treatments that can stop a miscarriage, although women
who are at risk and have not yet miscarried may be advised to rest in bed,
abstain from sexual activity, and restrict all activity until any warning signs
are no longer present. Once a miscarriage occurs, there is no treatment
available. In many cases, the miscarriage will take its course, and unless
there is severe pain and cramping or severe blood loss, no treatment is
required. If a miscarriage does not completely clear the pregnancy tissue from
the uterus, a procedure known as a
dilatation and curettage (D&C) can be
performed to remove the remaining pregnancy material. This treatment is used in
the case of a missed abortion, for example, when the pregnancy material is not
expelled from the uterus.
As mentioned above, women who are Rh-negative will receive a dose of rho-D
immune globulin to prevent complications in future pregnancies.
If a miscarriage is due to infection, antibiotic treatment will be given.
Miscarriage is such a common occurrence that typically, unless known risk
factors are present, no special testing is performed. For couples who have
experienced more than two miscarriages, diagnostic studies to detect genetic,
hormonal, or anatomical problems may be recommended. Some doctors recommend
evaluation of the couple after the second miscarriage, particularly if the
woman is over 35 years of age
What is the outlook for future pregnancies after a miscarriage?
Most women who miscarry go on to have a successful pregnancy. The likelihood
of a miscarriage in a future pregnancy increases with the number of
miscarriages a woman has had. In general, the risk of a second miscarriage in
women who have had a previous miscarriage is about 15%. The risk is about 30%
in women who have had two miscarriages. Most women will have their
menstrual period within 4 to 6 weeks after a
miscarriage. Your doctor can advise you when you may start trying to conceive
again. While it is possible to conceive again after your menstrual period has
returned, some doctors advise waiting a bit longer, such as another menstrual
cycle or more, to provide enough time for physical and emotional recovery.
Can
miscarriage be prevented?
There is no evidence that bed rest can help prevent miscarriage, but women
who have vaginal bleeding during pregnancy are often advised to rest and limit
sexual activity until there are no more potential signs of miscarriage. It is
possible that some risk factors for miscarriage can be minimized by maintaining
a healthy weight and avoiding the use of alcohol, illicit drugs, or tobacco.
Screening for and treatment of any
sexually-transmitted diseases (STDs) can also reduce the
risk of a miscarriage. Avoidance of sports such as horseback riding or skiing
can reduce your risk of trauma to the uterus. In most instances, however, the
cause of a miscarriage is outside of the woman's control
THANKS FOR YOUR RAPT ATTENTION……..
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