A miscarriage occurs when a pregnant woman's womb expels the unborn child and placenta before the infant is fully-grown. This may result from natural causes within the first 20 weeks of pregnancy. In an incomplete miscarriage, part of the tissue stays inside the womb.
What is going on in the body?
About fifteen to twenty percent of recognized pregnancies end in miscarriage. It is estimated, however, that counting pregnancies that are lost before they are recognized, the figure would be closer to 50 percent.
Eighty-five percent of recognized miscarriages take place in the first 12 weeks of pregnancy. This time is called the first trimester. These early miscarriages are most often the result of abnormalities in the unborn child. For example, the child may have abnormal chromosomes, or a genetic defect, that affects health and development.
On the other hand, miscarriages in the first half of the second trimester of pregnancy, that is, from 12 to 20 weeks, are most often caused by factors related to the mother. These may include maternal infections, chronic disease conditions, environmental exposures, or physical abnormalities of the uterus.
In a miscarriage, the baby and placenta stop growing, and pregnancy hormone levels fall. The following symptoms of pregnancy may disappear:
Then, the uterus starts to contract. This causes cramping, discomfort, and vaginal spotting or bleeding. A miscarriage is complete once the womb expels its contents. An incomplete miscarriage occurs when some of the tissue remains in the uterus and the cervix stays open. This may increase a woman's risk of infection and continued bleeding.
What are the causes and risks of the condition?
An unborn child that fails to develop or that is malformed most often causes miscarriages in the first 12 weeks of pregnancy.
Miscarriages in the second trimester are most often caused by factors related to the mother, such as:
- an abnormal-shaped womb, including one with a wall down the middle of it
- an age of 35 years or older
- autoimmune disorders, in which the woman's body creates antibodies to its own tissue, including fetal tissue. Systemic lupus erythematosus, an autoimmune disorder that involves many organ systems and is linked with a high risk of miscarriage, is one example.
- bacterial infections, such as the sexually transmitted diseasechlamydia
- certain other conditions and diseases, such as diabetes or hypothyroidism, a condition caused by low levels of thyroid hormones
- cervical incompetence, which means that the opening from the womb does not stay closed through the whole pregnancy
- cocaine use
- eating foods, such as chocolate and drinking liquids, such as coffee, that have caffeine in them
- noncancerous tumors in the womb, called fibroids
- exposure to chemical solvents and other toxins, such as paint thinners
- herbal remedies, which can cause birth defects as well as miscarriage. The March of Dimes advises that pregnant women avoid all dietary supplements, over-the-counter medicines, and prescription medicines unless recommended by their doctors.
- hormonal disorders, such as a low level of the female hormone progesterone
- polycystic ovary syndrome, a condition in which abnormal hormone levels cause growths within the ovary
- posttraumatic stress disorder, called PTSD, which occurs in some people who have gone through a major traumatic event
- viral infections, such as herpes, rubella, and cytomegalovirus, known as CMV, in the first trimester
A woman who has had three or more miscarriages in a row has a condition called habitual abortion.
What can be done to prevent the condition?
Not all miscarriages can be prevented. But taking certain actions can help. Several months before pregnancy and during the entire pregnancy, a woman should follow these guidelines:
Eat a diet rich in folic acid and take multivitamins that contain folic acid. This helps prevent birth defects such as neural tube defects and cleft lip or palate. It also helps a woman lay down a foundation of good nutrition.
Avoid all medicines unless recommended by the healthcare professional. This includes over-the-counter medicines, prescriptions, and herbal remedies.
Avoid alcohol and caffeine.
Stay away from pesticides and chemical solvents, such as paint thinners.
Maintain good control of diseases such as diabetes and hypothyroidism.
Report any symptoms of sexually transmitted disease to the healthcare professional.
Notify the healthcare professional of any other risk factors. This includes PTSD, polycystic ovary syndrome, or cervical incompetence. He or she can then help minimize the risk factor.
If a woman has had infertility tests for imbalanced hormones, the healthcare professional may screen her for first trimester hormone problems that could cause miscarriage. If a problem is found, hormones can be prescribed.
How is the condition diagnosed?
A blood or urine pregnancy test will be done to confirm a pregnancy. The level of the pregnancy hormone HCG may be checked several times over a period of days or weeks. Rising levels suggest that the unborn child is growing. Levels that fall or stay steady suggest little or no growth of a malformed or dying baby.
Other tests can include the following:
complete blood count (CBC) if the woman is bleeding heavily
white blood cell count to rule out infection
a progesterone level to find out if enough of the hormone is being made to maintain the pregnancy
pregnancy ultrasound to check for any fetal movement and heartbeat. The ultrasound can also rule out an ectopic pregnancy. This problem occurs when the egg implants outside of the uterus.
pelvic exam to see if the cervix is open and whether there is any fetal tissue in the vagina or the cervix
Long Term Effects
What are the long-term effects of the condition?
The long-term effects of an incomplete miscarriage vary. There are many myths about what causes miscarriage. A woman may feel anxiety, fear, and guilt if she believes she has "hurt her baby" by lifting heavy furniture, exercising too much, having sex, or doing something else to cause the miscarriage. A healthy pregnancy cannot be harmed by any of these activities. A woman should discuss feelings or worries such as these with her healthcare professional.
Delaying diagnosis and treatment of an incomplete miscarriage may increase a woman's risk of the following:
- developing Rh sensitization, which is a blood incompatibility that can harm a later pregnancy
- infertility from damage to the fallopian tubes
What are the risks to others?
An incomplete miscarriage is not contagious and poses no risk to others.
What are the treatments for the condition?
The treatments that may be used for an incomplete miscarriage include the following:
- dilatation and curettage, also called D&C, which is a procedure to remove any fetal tissue that remains in the womb following the miscarriage
- antibiotics to prevent infection
- medicines to help the womb contract so that bleeding subsides
- Rh immune globulin, if the mother's blood is Rh-negative. Otherwise, Rh sensitivity could affect later pregnancies and cause blood incompatibilities between the mother and baby.
What are the side effects of the treatments?
A D & C may be complicated by bleeding, infection, or an allergic reaction to the anesthetic. Antibiotics and medicines to help the womb contract may cause rash, upset stomach, abdominal cramps, or an allergic reaction.
What happens after treatment for the condition?
Within hours of having a D&C
, a woman is usually sent home to get better. She should rest in bed for 1 to 2 days. A woman should contact her healthcare professional if she has any of these symptoms:
- a fever
- cramps that get worse or pain that lasts
- continued heavy bleeding
- any other new or worsening symptoms
Birth control should be used if the woman does not wish to get pregnant again. If a future pregnancy is desired, a couple can try to conceive again after 2 to 3 months. They have an 85% chance of a successful, full-term pregnancy after 1 year.
How is the condition monitored?
A woman's healthcare professional may do weekly blood tests to follow the HCG level until it is nearly zero. This ensures that the pregnancy has ended. Sometimes, tests are done on the fetal tissue to learn about its genetic makeup. If a woman has had several miscarriages, her clinician may recommend a complete evaluation for infertility.