Miscarriage

A **miscarriage** is the natural death of an embryo or fetus in the womb, before it is old enough to live on its own, outside the mother.  The medical words for a miscarriage are **spontaneous abortion.**  ("Spontaneous" means something that a person did not expect to happen).

An "abortion" is when a pregnancy ends early, before birth.

Among women who know they are pregnant, about 15-20% have miscarriages.  (This means that up to 1 in every 5 women who know they are pregnant miscarries.)

## Miscarriage vs. Stillbirth
In the United States, if a fetus dies after it is 20 weeks old, its death is no longer called a miscarriage.  Its death is called a *stillbirth*, a *fetal demise*, or a *fetal death*.  ("Demise" means "death.") Different countries have different ways of defining the difference between a miscarriage and a fetal death.  For example:

## Causes of miscarriage
Nobody knows all of the reasons why a woman may miscarry.  However, some common causes include:
* Genetic problems, like aneuploidy
* Problems with the mother's uterus or hormones
* An infection somewhere in the mother's reproductive system
* Tissue rejection (where the mother's body reacts to the fetus like it is something that does not belong in her body)
* Serious physical trauma (injury, like a bad car accident
* Very rarely, medical procedures that are used to diagnose problems with the fetus can cause miscarriage.  This happens in only about 1% of cases (1 out of 100) when a woman has had chorionic villus sampling (CVS) or amniocentesis)

The most common causes of miscarriage change depending on what trimester the mother is in.  (Each trimester lasts about three months.)

### First trimester (Weeks 1-12)
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Most miscarriages happen during the first trimester.  Some studies say that two-thirds (two out of three) to three-quarters (three out of four) of all miscarriages happen during this trimester. About 30% to 40% (3 to 4 in every 10) of all fertilized eggs miscarry, often before a woman knows she is pregnant.

In more than half of embryos miscarried in the first 13 weeks of pregnancy, the embryo has chromosomes that are not normal. These chromosomal problems may happen because of problems as the embryo grows and its cells make copies of themselves.  It is also possible for chromosomal problems to happen because of a problem with a parent's genes.  However, this is more likely to happen in women who have had other miscarriages, or if one of the parents has a child or other relatives with birth defects. Genetic problems are more likely to happen with older parents; this may be why miscarriages are more common in older women.

Another cause may be the mother not having enough progesterone.  If a woman is diagnosed with low progesterone levels in the second half of her menstrual cycle (the luteal phase), she may be prescribed progesterone, to take during the first trimester of her pregnancy.  Scientists have even questioned whether problems with the luteal phase really can cause miscarriages.

### Second trimester (Weeks 13-27)
Common causes of miscarriage during the second trimester are: Problems with the placenta may also cause second-trimester miscarriages.

Usually, if a pregnant woman is bleeding or having pain, an ultrasound should be done.  The ultrasound can show that the fetus's heart is not beating, which means that the fetus has miscarried.  If this happens, special tests should be done to make sure the woman does not have an ectopic pregnancy, which can kill a woman.

Not all light bleeding during early pregnancy means a woman is having a miscarriage.  But any woman having light bleeding during pregnancy should see her doctor.  If the bleeding is heavy, the woman is having a lot of pain, or she has a fever, she should go to an Emergency Room or call an ambulance to take her to the hospital.

## Treatment
There are a few different types of miscarriage:
* In a *complete miscarriage*, the fetus has totally left the mother's body.  So has the placenta.  There are no pieces of fetal or placental tissue left in the uterus.
* In a *missed miscarriage*, the fetus has miscarried but is still inside the mother's body.  This often happens when the mother does not realize she had a miscarriage (which is common when the pregnancy is very early on).
* In an *incomplete miscarriage*, parts of the fetus or the placenta are still in the uterus.

The treatment is different for each kind of miscarriage.

### Complete miscarriage
If a woman has a complete miscarriage, she usually does not need any medical treatment.  This path avoids the side effects and complications possible from medications and surgery, but increases the risk of mild bleeding, need for unplanned surgical treatment, and incomplete miscarriage.
*Medical Management means that medicine is given.  Usually, a medicine called misoprostol is given.  Misoprostol makes the uterus contract (get tighter) to push out whatever is inside.  In about 95% of cases (95 out of 100), the fetal or placental tissue that is left in the uterus will leave the woman's body within a few days.  
* For embryos that were less than 7 weeks old, and the smallest gestational sacs, watchful waiting is the best choice, because the embryo will often leave the mother's body naturally.
* For embryos that were 7–9 weeks old with larger sizes and gestational sacs, medicine is suggested, but either watchful waiting or surgery might be used depending on the situation.  
* For the embryos that were over 9 weeks old, with the largest gestational sacs, surgery is suggested because the mother is likely to have a lot of pain and bleeding when she miscarries.

*Incomplete Miscarriages*

* For an incomplete miscarriage, the size of the tissue left in the uterus is the most important thing that helps doctors decide what to do.  Ultrasound is used to find out how large the tissue is.
* The age of the mother.  Women older than age 35 have a higher risk of miscarriage than younger women. At age 35, a woman has about a 20 percent risk. At age 40, the risk is about 40 percent. And at age 45, it's about 80 percent.
* If the mother has certain diseases, like:
** Diabetes, especially the mother needs insulin and her diabetes is still not controlled well.
** Hypothyroidism, especially when the hypothyroidism is very bad.
** Some infections, like HIV, rubella, malaria, and some sexually transmitted diseases like chlamydia, gonorrhea, and syphilis.
* If the mother or father smokes tobacco (cigarettes). 
* If the mother drinks alcohol while she is pregnant, especially if she drinks often, or drinks a lot at once.
* Problems with the mother's uterus or cervix.
* Some types of food poisoning.

## Related pages 
* Congenital disabilities that can cause miscarriage
* Ultrasound (used to diagnose miscarriage)
* Dilation and curettage
* Dilation and evacuation
* Stillbirth

## References