A miscarriage is the spontaneous loss of a fetus before the 20th week of pregnancy (pregnancy losses after the 20th week are called stillbirths). Miscarriage is a naturally occurring event, unlike medical or surgical abortions.
A miscarriage may also be called a "spontaneous abortion." Other terms for the early loss of pregnancy include:
Your health care provider may also use the term "threatened miscarriage." The symptoms of this condition are abdominal cramps with or without vaginal bleeding. They are a sign that a miscarriage may occur.
Most miscarriages are caused by chromosome problems that make it impossible for the baby to develop. In rare cases, these problems are related to the mother's or father's genes.
Other possible causes of miscarriage may include:
Around half of all fertilized eggs die and are lost (aborted) spontaneously, usually before the woman knows she is pregnant. Among women who know they are pregnant, about 10% to 25% will have a miscarriage. Most miscarriages occur during the first 7 weeks of pregnancy. The rate of miscarriage drops after the baby's heartbeat is detected.
The risk of miscarriage is higher:
Possible symptoms of miscarriage may include:
During a pelvic exam, your provider may see that your cervix has opened (dilated) or thinned out (effacement).
Abdominal or vaginal ultrasound may be done to check the baby's development and heartbeat, and the amount of your bleeding.
The following blood tests may be performed:
When a miscarriage occurs, the tissue passed from the vagina should be examined. This is done to determine if it was a normal placenta or a hydatidiform mole (a rare growth that forms inside the womb early in pregnancy). It is also important to find out whether any pregnancy tissue remains in the uterus. In rare cases an ectopic pregnancy can look like a miscarriage. If you have passed tissue, ask your provider if the tissue should be sent for genetic testing. This can be helpful to determine if a treatable cause of miscarriage is present.
If the pregnancy tissue does not naturally leave the body, you may be closely watched for up to 2 weeks. Surgery (suction curettage, D and C) or medicine may be needed to remove the remaining contents from your womb.
After treatment, women usually resume their normal menstrual cycle within 4 to 6 weeks. Any further vaginal bleeding should be carefully monitored. It is often possible to become pregnant immediately. It is suggested that you wait one normal menstrual cycle before trying to become pregnant again.
In rare cases, complications of miscarriage are seen.
An infected abortion may occur if any tissue from the placenta or fetus remains in the uterus after the miscarriage. Symptoms of an infection include fever, vaginal bleeding that does not stop, cramping, and a foul-smelling vaginal discharge. Infections can be serious and need immediate medical attention.
Women who lose a baby after 20 weeks of pregnancy receive different medical care. This is called premature delivery or fetal demise. This needs immediate medical attention.
After a miscarriage, women and their partners may feel sad. This is normal. If your feelings of sadness do not go away or get worse, seek advice from family and friends as well as your provider. However, for most couples, a history of a miscarriage doesn't reduce the chances of having a healthy baby in the future.
Call your provider if you:
Early, complete prenatal care is the best prevention for complications of pregnancy, such as miscarriage.
Miscarriages that are caused by systemic diseases can be prevented by detecting and treating the disease before pregnancy occurs.
Miscarriages are also less likely if you avoid things that are harmful to your pregnancy. These include x-rays, recreational drugs, alcohol, high caffeine intake, and infectious diseases.
When a mother's body has difficulty keeping a pregnancy, signs such as slight vaginal bleeding may occur. This means there is a risk of miscarriage. But it does not mean one will definitely occur. A pregnant woman who develops any signs or symptoms of threatened miscarriage should contact her prenatal provider instantly.
Taking a prenatal vitamin or folic acid supplement before you become pregnant can greatly lower the chances of miscarriage and certain birth defects.
Reviewed By: John D. Jacobson, MD, Professor of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda Center for Fertility, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.