There are various ways in which a pregnancy may be lost. Miscarriage means loss of an embryo or fetus before the 20th week of pregnancy. Most miscarriagesoccur during the first 14 weeks of pregnancy. The medical term for miscarriage is spontaneous abortion.
An abnormally weak cervix (the structure at the bottom of the uterus) is called "incompetent," and therefore it can gradually widen during pregnancy. Leftuntreated, this can result in repeated pregnancy losses or premature delivery.
A stillbirth is defined as the death of a fetus at any time after the 20th week of pregnancy. Stillbirth is also referred to as intrauterine fetal death (IUFD).
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.
Incompetent cervix is the result of an anatomical abnormality. Normally, thecervix remains closed throughout pregnancy until labor begins. An incompetentcervix gradually opens due to the pressure from the developing fetus after about the 13th week of pregnancy. The cervix begins to thin out and widen without any contractions or labor. The membranes surrounding the fetus bulge downinto the opening of the cervix until they break, resulting in the loss of the baby or a very premature delivery.
It is important to distinguish between a stillbirth and other words that describe the unintentional end of a pregnancy. A pregnancy that ends before the 20th week is called a miscarriage rather than a stillbirth, even though the death of the fetus is a common cause of miscarriage. After the 20th week, the unintended end of a pregnancy is called a stillbirth if the infant is dead atbirth and premature delivery if it is born alive.
Factors that increase a mother's risk of stillbirth include: age over 35; malnutrition; inadequate prenatal care; smoking; and alcohol or drug abuse.
There are many reasons why a woman's pregnancy ends in miscarriage. Often thecause 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. Theseare different from inherited genetic diseases. They probably occur during development of the specific egg or sperm, and therefore are not likely to occuragain.
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 aproblem with the structure of the uterus or cervix. This can especially occurin 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 pregnancy
- Poorly-controlled diabetes.
The most common symptom of miscarriage is bleeding from the vagina, which maybe light or heavy. However, bleeding during early pregnancy is common and isnot 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 additionto 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 pregnantwoman experiences both bleeding and cramping the possibility of miscarriageis 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, miscarriageis inevitable and nothing can preserve the pregnancy. Symptoms of an inevitable miscarriage may include dull relentless or sharp intermittent pain in thelower 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 norplacenta is expelled. There may not be any bleeding or pain, but the symptomsof pregnancy will disappear. The physician may suspect a missed abortion ifthe 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.
Some factors that can contribute to the chance of a woman having an incompetent cervix include trauma to the cervix, physical abnormality of the cervix, or having been exposed to the drug diethylstilbestrol (DES) in the mother's womb. Some women have cervical incompetence for no obvious reason.
A number of different disorders can cause stillbirth. They include:
- Pre-eclampsia and eclampsia. These are disorders of late pregnancy characterized by high blood pressure, fluid retention, and protein in the urine.
- Diabetes in the mother.
- Abnormalities in the fetus caused by infectious diseases, including syphilis, toxoplasmosis, German measles (rubella), and influenza.
- Severe birth defects, including spinabifida. Birth defects are responsible for about 20% of stillbirths.
- Postmaturity. Postmaturity is a condition in which the pregnancy has lasted 41 weeks or longer.
- Unknown causes. These account for about a third ofstillbirths.
In most cases the only symptom of stillbirth is that the mother notices thatthe baby has stopped moving. In some cases, the first sign of fetal death ispremature labor. Premature labor is marked by a rush of fluid from the vagina, caused by the tearing of the membrane around the baby; and by abdominal cramps or contractions.
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 itshould 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.
Incompetent cervix is suspected when a woman has three consecutive spontaneous pregnancy losses during the second trimester (the fourth, fifth and sixth months of the pregnancy). The likelihood of this happening by random chance isless than 1%. Spontaneous losses due to incompetent cervix account for 20-25% of all second trimester losses. A spontaneous second trimester pregnancy loss is different from a miscarriage, which usually happens during the first three months of pregnancy.
The physician can check for abnormalities in the cervix by performing a manual examination or by an ultrasound test. The physician can also check to see if the cervix is prematurely widened (dilated). Because incompetent cervix isonly one of several potential causes for this, the patient's past history ofpregnancy losses must also be considered when making the diagnosis.
When the mother notices that fetal movement has stopped, the doctor can use several techniques to evaluate whether the baby has died. The doctor can listen for the fetal heartbeat with a stethoscope, use Doppler ultrasound to detect the heartbeat, or give the mother an electronic fetal nonstress test. In this test, the mother lies on her back with electronic monitors attached to herabdomen. The monitors record the baby's heart rate, movements, and contractions of the uterus.
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, womenshould drink fluids only.
Although it may be psychologically difficult, if a woman has a miscarriage athome she should try to collect any material she passes in a clean containerfor 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 procedurethe 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.
Treatment for incompetent cervix is a surgical procedure called cervical cerclage. A stitch (suture) is used to tie the cervix shut to give it more support. It is most effective if it is performed somewhere between 14-16 weeks intothe pregnancy. The stitch is removed near the end of pregnancy to allow fora normal birth.
Cervical cerclage can be performed under spinal, epidural, or general anesthesia. The patient will need to stay in the hospital for one or more days. Theprocedure to remove the suture is done without the need for anesthesia. The vagina is held open with an instrument called a speculum and the stitch is cutand removed. This may be slightly uncomfortable, but should not be painful.
Some possible risks of cerclage are premature rupture of the amniotic membranes, infection of the amniotic sac, and preterm labor. The risk of infection of the amniotic sac increases as the pregnancy progresses. For a cervix that is dilated 3 centimeters (cm), the risk is 30%.
After cerclage, a woman will be monitored for any preterm labor. The woman needs to consult her obstetrician immediately if there are any signs of contractions.
Cervical cerclage can not be performed if a woman is more than 4 cm dilated,if the fetus has already died in her uterus, or if her amniotic membranes aretorn and her water has broken.
In most cases of intrauterine death, the mother will go into labor within twoweeks of the baby's death. If the mother does not go into labor, the doctorwill bring on (induce) labor in order to prevent the risk of hemorrhage. Labor is usually induced by giving the mother a drug (oxytocin) that cause the uterus to contract.
Emotional support from family and friends, self-help groups, and counseling by a mental health professional can help bereaved parents cope with their loss.
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 success rate for cerclage correction of incompetent cervix is good. About80-90% of the time women deliver healthy infants. The success rate is higherfor cerclage done early in pregnancy.
With the exception of women with diabetes, women who have a stillbirth have as good a chance of carrying a future pregnancy to term as women who are pregnant for the first time.
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 afew 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), thiscan be treated with a hormone called progesterone to help prevent subsequentmiscarriages. If structural problems have led to repeated miscarriage, thereare some possible procedures to treat these problems. Other possible ways toprevent miscarriage are to treat genital infections, eat a well-balanced diet, and refrain from smoking and using recreational drugs.
The risk of stillbirth can be lowered to some extent by good prenatal care and the mother's avoidance of exposure to infectious diseases, smoking, alcoholabuse, or drug consumption. Tests before delivery (antepartum testing), suchas ultrasound, the alpha-fetoprotein blood test, and the electronic fetal nonstress test, can be used to evaluate the health of the fetus before there isa stillbirth.