Understanding Miscarriage


One of the most devastating events in a couple's life is the loss of their baby through a miscarriage or stillbirth. Even though magazines and other media sources have begun discussing this sensitive subject, most people are unaware that a high number of all pregnancies end in a miscarriage, usually during the first few weeks of pregnancy.

One of the most devastating events in a couple's life is the loss of their baby through a miscarriage or stillbirth. Even though magazines and other media sources have begun discussing this sensitive subject, most people are unaware that a high number of all pregnancies end in a miscarriage, usually during the first few weeks of pregnancy. Since this is such a common and serious problem, it is important to understand the possible causes of miscarriage, the appropriate evaluation for patients who have recurrent miscarriages, and what to say (and not say) to a friend or loved one who has had a pregnancy loss.

Technically, a miscarriage is any pregnancy loss that occurs during the first 20 weeks of pregnancy, which is approximately up to the 5th month. (The formal medical term for a miscarriage is "spontaneous abortion," but many doctors disagree with this terminology because of the confusion this creates with pregnancy terminations, which are also called "abortions"). Miscarriages are unfortunately very common. Most people are unaware that up to 1/2 of all early pregnancies end as a miscarriage! Many of these are so early the patient does not even know she is pregnant. Others cause symptoms, such as cramping, bleeding, or perhaps the passage of clots from the vagina. Most researchers agree that about 20% of all pregnancies end up as the type of miscarriage that causes symptoms, while the rest are "silent" and do not cause significant symptoms. The overwhelming majority of miscarriages occur in the first trimester; far fewer occur in the second trimester. Stillbirth is the term used by many to describe a pregnancy loss during the last stages of pregnancy.

Women with symptoms like bleeding, cramping, or passing tissue or large clots should notify their doctor. Sadly, there is almost never anything you or your doctor can do to prevent a miscarriage once symptoms occur, and while some doctors and midwives advise bed rest, this has actually not been proven to help prevent miscarriage. Others advise starting progesterone supplements once the signs of a miscarriage occur, although this, too, has not been proven to be helpful. Most health care providers do suggest limited activity and abstinence from intercourse or heavy exercise. In some cases a thorough pelvic examination and perhaps an ultrasound (sometimes also called a sonogram) will help determine if their has been a miscarriage or if the fetus is still viable (in other words, if the baby still has a heartbeat). In other cases the patient may need special blood "pregnancy hormone" studies called beta-HCG levels to help determine if the pregnancy has a chance at survival. Following these levels over many days may be useful in determining whether or not a miscarriage is occurring. It is not necessary to follow these levels in all cases.

Once a miscarriage is diagnosed the patient has the option of awaiting passage of all the placental tissue, or having a D&C (dilatation and curettage) of the uterus to remove the tissue via outpatient surgery. This is a very individual decision that requires discussion between the patient and her doctor. In my experience most women who desire an immediate D&C do so for psychological reasons. Contrary to popular belief, a D&C has never been proven to "clean you out" and make subsequent pregnancies easier. It is a surgical procedure with certain (although uncommon) risks, such as bleeding, infection, or the formation of intra-uterine scar tissue that may complicate future pregnancies. On the other hand, some women desire to await "natural" passage of the placental and fetal tissue, and while in very rare situations this may lead to excess bleeding or infection, it is perfectly acceptable to wait for nature to take it's course. Since it may take weeks for this to happen, it requires close consultation between the patient and her health care provider. As mentioned earlier, the term spontaneous abortion is "medicalese" for miscarriage so this may appear on a hospital bill or operative report, and in no way implies the patient voluntarily terminated the pregnancy.

A number of problems can cause both isolated or recurrent pregnancy losses. The most common, by far, is a chromosomal abnormality where the genetic material from the sperm and egg do not fuse together appropriately. This accounts for about 1/2 of all miscarriages and is most commonly a random event that is, essentially, very bad luck. A variation of this is when a "blighted ovum" occurs, where the water bag and placenta (afterbirth) develop but not the fetus (baby). Fortunately, in about 9 out of 10 cases the next pregnancy after these types of miscarriage is normal! For this reason the overwhelming majority of doctors do not advise a complex evaluation after a single, first-trimester miscarriage. However, consecutive miscarriages, and especially pregnancy losses that occur later in pregnancy, often need a thorough evaluation. Doctors can find a cause of recurrent miscarriage about 1/2 of the time. Couples need to realize that they did not do anything wrong that may have caused a miscarriage. Miscarriage is a devastating situation that is only made worse by unecessary guilt. Sexual activity, excercise, a normal diet, bathing, swimming, and working in a reasonably normal job have never been significantly linked to pregnancy losses.

An abnormality of the uterus (womb) may cause about 15% of recurrent miscarriages. In this situation the uterine muscle is slightly malformed and the pregnancy cannot grow appropriately. This problem is diagnosed with a special x-ray or ultrasound of the uterus and surgery to correct the defective area is usually successful in curing the problem.

Some unusual vaginal infections can cause recurrent miscarriages, although it appears that this is not common. Cultures of the vagina and antibiotics are sometimes helpful if your doctor suspects an infection. Common infections such as yeast infections have not been linked to pregnancy losses.

Another condition that can cause pregnancy losses, particularly in the second trimester, is "incompetent cervix," where the opening between the uterus and vagina, called the cervix, is not strong enough to hold the pregnancy. In this situation the patient feels an abnormal amount of pressure, and may either deliver a baby that is too small to survive, or may break her water bag, which quite often (but not always) leads to preterm labor. Preterm labor with delivery of a tiny baby, is, of course, another cause of pregnancy loss.

Rarely (about 3% of the time), a chromosomal problem of one or both partners can lead to recurrent pregnancy loss. This problem, usually a "balanced translocation" of one or both parents' chromosomes, is diagnosed by taking a blood or tissue sample from each partner and performing a 'karyotype' to check the chromosomes. There is a higher rate of miscarriages in patients who have such a chromosomal problem, although many go on to deliver normal and healthy babies. Once diagnosed with this condition a thorough discussion with a genetics counselor will help the parents decide upon trying for a future pregnancy or opting for adoption.

Autoimmune problems, where certain chemicals in the blood stream attack cells and tissues within the body, can lead to pregnancy loss. These chemicals, called 'antibodies,' circulate in the blood stream and may never cause problems, or they may lead to disorders such as diabetes, lupus, antiphospholipid syndrome, or hypothyroidism. They can also lead to blood clots in the placenta, which shuts off the blood supply to the developing baby, causing a miscarriage. Special blood tests can diagnose this problem, and treatment with low-dose aspirin and sometimes an injection of a 'blood thinner' called heparin will usually lead to a successful pregnancy. These are "high-risk" pregnancies because of an increased chance of small babies, fetal stress, preeclampsia ('toxemia', where the blood pressure rises dangerously during pregnancy), and other problems, and special monitoring of the pregnancy is often required.

During pregnancy a benign cyst on the ovary, called the corpus luteum, produces the hormone progesterone which is necessary for maintaining the pregnancy during the first trimester. Although somewhat controversial, some doctors feel a "luteal phase defect" can cause recurrent pregnancy>loss. This condition may occur when not enough progesterone is present to act on the lining of the uterus. Diagnosis is made when 2 endometrial biopsies are performed a few months apart, by taking a sample of tissue from the uterine lining in the doctor's office. Treatment is usually with either progesterone supplements, or a medication called clomiphene citrate, both of which seem to provide enough progesterone to allow the pregnancy to "take hold" during the first trimester. After that, the placenta makes enough of it's own progesterone. Again, once a miscarriage is in progress, it is extremely doubtful that supplementation of progesterone or any other medication will help prevent a miscarriage.

Finally, a very controversial potential cause of recurrent miscarriages is an allo-immune disorder, where the man and woman have too much genetic material in common. The theory is that the mother's body 'rejects' the fetus in a way similar to how a transplant patient might reject a new organ. Some doctors advocate extensive (and expensive) testing to diagnose this condition, and use injections of the male partner's white blood cells into the female partner's blood stream to help prevent future miscarriages. Others advocate immunoglobulin injections. However, many experts in this field disagree with this testing and treatment, saying that research is lacking to prove that it is helpful. Many feel that doctors should not attempt such expensive testing and treatment until further research proves that this therapy is helpful. Embarking on a controversial form of therapy such as this requires a great deal of thought on the part of the patient, and a thorough discussion of the potential risks and benefits with her physician.

Many of the problems already mentioned can also cause a stillbirth. Some other causes of stillbirths include severe diabetes, lupus, fetal growth restriction, alcohol or drug abuse, tobacco abuse, a "tear" in the placenta called an abruption, high blood pressure, intrauterine infections, significant maternal trauma (such as a bad car accident), a "ruptured" uterus, or problems with the blood supply between the placenta and the baby, or within the umbilical cord. Once a stillbirth is diagnosed, the mother has the option of either awaiting natural labor, or undergoing an induction of labor. A c/section is usually not performed in this situation since c/sections are major abdominal surgeries that can cause complications for the mother.

If you have a friend or family member who has gone through a miscarriage, there is much you can do to help her (and her partner). First, simply letting her know that you are very sorry to hear of her loss is the kindest thing you can do. Letting her know that you are available to help or listen is another good suggestion. Most women who have had a miscarriage will find either or both of these quite adequate and helpful. Unfortunately, most of us feel awkward when faced with a friend in emotional pain, and we feel obligated to say something else. Sadly, what we attempt to say in these sensitive situations may not come across right and we may instead say something profoundly hurtful and insensitive. In fact, most women who have had a miscarriage tell me that they have heard unbelievably insensitive comments from their friends and family, and in some cases this has led to permanently damaged relationships. Comments such as "the baby would have been deformed anyway," "it must be punishment for something you did wrong," or even "you can always have more" can be extremely painful to a woman and her partner. A similarly disturbing comment is "how can you be so upset; you were barely pregnant?" Women and their partners who suffer a miscarriage often have severe grief over the loss of their baby. It does not matter how far along the mother was at the time of her loss, and, in fact, many women grieve as much over the loss of a baby in the first trimester as they do for a stillborn baby or a baby that dies many months or years after birth. Grief is very individual, and friends and loved ones should try to be kind and supportive through this difficult process.

In summary, miscarriage is very common and may be caused by a number of problems. Fortunately, there is about a 90% chance that the next pregnancy following a miscarriage will be normal. In more unusual situations a problem may exist that leads to recurrent pregnancy losses. Fortunately, patients who have recurrent pregnancy losses can often be successfully treated so that they are able to carry a baby to full term. Supportive, patient, and nonjudgmental friends and family members can be extremely helpful to the couple who have suffered a miscarriage.


D. Ashley Hill, M.D.

Associate Director

Department of Obstetrics and Gynecology

Florida Hospital Family Practice Residency

Orlando, Florida


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