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(Spontaneous Abortion; Pregnancy Loss)


Aparna Sridhar

, MD, UCLA Health

Reviewed/Revised Jan 2024
Topic Resources

A miscarriage is a pregnancy loss before 20 weeks of pregnancy.

  • Miscarriages are very common, especially early in pregnancy.

  • Most of the time, the cause of a miscarriage is unknown, but it may occur because the fetus is not developing normally (sometimes because of a genetic abnormality or birth defect) or because of a health issue in the pregnant woman such as a structural abnormality of the reproductive organs, infection, use of substances (for example, cocaine, alcohol, or cigarette smoking), or an injury.

  • Bleeding and cramping may be symptoms of a miscarriage.

  • Doctors check the fetal status with ultrasonography and do a pelvic examination.

  • If a miscarriage is confirmed, a woman may wait to pass the pregnancy tissue, or she may take medications or have a procedure to help with this process.

A miscarriage occurs in about 10 to 15% of confirmed pregnancies. Many more miscarriages are unrecognized because they occur before a woman knows she is pregnant. About 85% of miscarriages occur during the first 12 weeks of pregnancy. The remaining 15% of miscarriages occur during weeks 13 to 20. When a woman wants to be pregnant and have a child, a miscarriage is often emotionally difficult for her and her partner, and they may need support from loved ones and health care professionals.

Miscarriages are more common in high-risk pregnancies High-Risk Pregnancy , particularly when women are not receiving adequate medical care.

Causes of Miscarriage

Most often, the cause of miscarriage is unknown.

Miscarriages that occur during the first 10 to 11 weeks of pregnancy are often caused by a chromosome disorder Overview of Chromosome and Gene Disorders Chromosomes are structures within cells that contain a person's genes. Genes are segments of deoxyribonucleic acid ( DNA) and contain the code for a specific protein that functions in one or... read more . This occurs more frequently in women who are younger than 20 years old or are 35 or older.

Risk factors (conditions that increase the risk of a disorder) for miscarriage include the following:

Major physical trauma can cause miscarriage, but it is unlikely to be caused by minor force or injury (such as from slipping and falling or exercise). Sudden emotional shock (for example, from receiving bad news) is not linked with miscarriage.

Understanding the Language of Pregnancy Loss

Doctors may use the term abortion to refer to a miscarriage, because the medical term is spontaneous abortion. The medical term for intentional termination of pregnancy is called induced abortion or voluntary interruption of pregnancy.

Terms for abortion include the following:

  • Miscarriage (spontaneous abortion): Pregnancy loss before 20 weeks of pregnancy

  • Early miscarriage: Pregnancy loss before 12 weeks of pregnancy

  • Late miscarriage: Pregnancy loss between 12 and 20 weeks of pregnancy

  • Threatened abortion: Bleeding or cramping during the first 20 weeks of pregnancy but without opening (dilation) of the cervix

  • Missed abortion: Fetal demise detected with ultrasonography before 20 weeks of pregnancy, without symptoms (bleeding or pain) that suggested a problem with the pregnancy

  • Recurrent miscarriage: A history of at least 3 miscarriages

  • Septic abortion: Infection of the contents of the uterus before, during, or after a miscarriage or an induced abortion

  • Stillbirth: Fetal death and delivery at 20 or more weeks of pregnancy

Symptoms of Miscarriage

A miscarriage is usually preceded by vaginal bleeding, which may be spotting with bright or dark red blood or heavier bleeding. The uterus is a muscle, and it contracts during miscarriage, causing cramps. This may cause the cervix to open (dilate). However, vaginal bleeding is common in early pregnancy and often there is no problem with the pregnancy. About 25% of pregnant women have some bleeding at least once during the first 12 weeks of pregnancy. Approximately 12% of pregnancies with bleeding during the first 12 weeks result in a miscarriage.

Early in a pregnancy, the only sign of a miscarriage may be a small amount of vaginal bleeding. Later in a pregnancy, a miscarriage may cause profuse bleeding, and the blood may contain mucus or clots. Cramps become more severe until, eventually, the uterus contracts enough to expel the fetus and placenta.

Sometimes a fetus stops developing, but no symptoms of miscarriage occur. This is called a missed abortion. Doctors may suspect a missed abortion if the uterus does not enlarge. Sometimes, doctors detect a missed abortion on a routine prenatal ultrasound.

If any fragments of a fetus or placenta remain in the uterus after a miscarriage, infection may develop. Infection of the uterus that occurs during or shortly before or after a miscarriage or induced abortion is called a septic abortion Septic Abortion Septic abortion is a serious infection of the uterus that occurs shortly before, during, or after an abortion or a miscarriage. Septic abortion is a medical emergency. Septic abortion causes... read more . This infection can be very serious and even life threatening. A woman should seek medical care if abdominal pain or vaginal bleeding persists or worsens a few days after a miscarriage or if she has a fever.

Did You Know...

  • Miscarriages are common in early pregnancy, and some may not be recognized because they occur before women know they are pregnant.

  • About 25% of pregnant women have some bleeding at least once during the first 12 weeks of pregnancy, but only about 12% of these women have a miscarriage.

Diagnosis of Miscarriage

  • A doctor's evaluation

  • Ultrasonography

  • Blood tests

If a pregnant woman has bleeding and cramping during the first 20 weeks of pregnancy, a doctor examines her to determine whether a miscarriage is likely. During a pelvic examination Pelvic Examination For gynecologic care, a woman should choose a health care practitioner with whom she can comfortably discuss sensitive topics, such as sex, birth control, pregnancy, and problems related to... read more , a doctor examines the cervix to determine whether it is dilating. If it is not, the pregnancy may be able to continue. If it is dilating before 20 weeks of pregnancy, a miscarriage is highly likely.

Sometimes a doctor uses a device to listen for the fetal heartbeat. Also, ultrasonography is done using a device inserted into the vagina (called transvaginal ultrasonography). Ultrasonography may be used to determine whether a miscarriage has already occurred or, if not, whether the fetus is still alive. If a miscarriage has occurred, ultrasonography can show whether the fetus and the placenta have been completely expelled.

Usually, doctors do blood tests to measure a hormone produced by the placenta early in pregnancy called human chorionic gonadotropin (hCG). Results confirm the pregnancy. Usually, the test is repeated every several days or once a week to determine whether a woman has a mislocated (ectopic) pregnancy Ectopic Pregnancy Ectopic pregnancy is attachment (implantation) of a fertilized egg in an abnormal location, such as a fallopian tube. In an ectopic pregnancy, the fetus cannot survive. Women with an ectopic... read more , which can also cause bleeding, and also to make sure that the miscarriage process has been completed.

If the uterus does not progressively enlarge, doctors suspect a missed abortion. That is, the fetus has died but has not been expelled from the uterus or caused symptoms (vaginal bleeding or abdominal pain).

If a woman has had 2 or more miscarriages, she may want to see a doctor before trying to become pregnant again. The doctor can check for genetic or structural abnormalities and for other disorders that increase the risk of a miscarriage. For example, doctors may do the following:

  • An imaging test (such as ultrasonography, hysteroscopy, or hysterosalpingography) to look for structural abnormalities of the female reproductive system

  • Blood tests to check for certain disorders, such as antiphospholipid syndrome, diabetes, reproductive hormone abnormalities, and thyroid disorders

  • Genetic tests to check for chromosome abnormalities

If identified, some causes of recurrent miscarriage can be treated, making a successful pregnancy possible in the future.

Treatment of Miscarriage

  • No treatment, if the pregnancy tissue has completely passed

  • Observation of symptoms and waiting for the pregnancy tissue to pass on its own

  • Medications or a procedure to help remove the pregnancy tissue

  • Pain medication, as needed

  • Rho(D) immune globulin if the mother has Rh-negative blood

  • Emotional support

If there is a threatened miscarriage (symptoms are occurring but ultrasonography shows a normal pregnancy), some doctors advise women to avoid strenuous activity and, if possible, to stay off their feet and avoid sexual activity. However, there is no clear evidence that such limitations are helpful.

If a miscarriage is confirmed and the fetus and the placenta have been completely expelled, no further treatment is needed.

If a miscarriage is confirmed, but all or some of the tissue from the fetus or placenta remains in the uterus, there are usually several options for passing or removing the pregnancy tissue.

For an early miscarriage (before 12 weeks of pregnancy), if a woman does not have heavy bleeding or signs of infection, doctors usually explain several options, and a woman may choose to do one of the following:

  • Closely monitor symptoms and wait for the uterus to expel the tissue on its own: A woman should receive instructions about what to expect, how to manage pain, how to recognize if the pregnancy tissue has passed, and when to call a doctor (if bleeding or pain is different than the usual for a miscarriage or a fever occurs). If the pregnancy tissue does not pass on its own, medication or a procedure is necessary.

  • Take medication (usually misoprostol, sometimes with mifepristone) to help the uterus expel the pregnancy.

  • Have a procedure to remove the pregnancy tissue from the uterus: Usually, a flexible tube is inserted through the vagina into the uterus and suction is used (dilation and curettage [D & C] with suction Surgical abortion ).

If a miscarriage has passed on its own, doctors usually do blood tests for the pregnancy hormone hCG once a week until the level is undetectable, to confirm that no tissue from the fetus or placenta remains in the uterus.

For a late miscarriage (between 12 and 20 weeks), doctors usually advise not to wait for the pregnancy to pass on its own, because this may cause serious pain or bleeding, and the pregnancy may not pass completely, causing infection. Late miscarriages are treated with one or more of the following options:

Pain relievers are given as needed.

Emotions after miscarriage

After a miscarriage, a woman and her partner may feel grief, sadness, anger, guilt, or anxiety about subsequent pregnancies.

  • Grief: Grief for a loss is a natural response and should not be suppressed or denied. Talking about their feelings with another person may help women deal with their feelings and gain perspective.

  • Guilt: Women may think that they did something to cause the miscarriage. Usually, they have not. Women may recall taking a common over-the-counter medication early in pregnancy, drinking a glass of wine before they knew they were pregnant, or doing another everyday thing. These things are almost never the cause of a miscarriage, so women should not feel guilty about them.

  • Anxiety: Women who have had a miscarriage may wish to talk with their doctor about the likelihood of a miscarriage in subsequent pregnancies and be tested if needed. Although having a miscarriage increases the risk of having another one, most of these women can become pregnant again and carry a healthy baby to term. Additional testing is usually not necessary unless women have had 2 or more miscarriages.

Doctors offer their support and, when appropriate, reassure women that the miscarriage was not their fault. Formal counseling is rarely needed, but doctors make it available for women who want it. Support groups may be helpful.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Korlym, Mifeprex
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