Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link



The Manual's Editorial Staff

Reviewed/Revised May 2023
Get the full details

What is a miscarriage?

Miscarriage is when your pregnancy ends before 20 weeks of pregnancy. Most miscarriages happen in the first 12 weeks of pregnancy.

What causes a miscarriage?

Doctors don't always know what causes you to miscarry. Miscarriage is not caused by a sudden emotional shock, such as getting bad news. Also, minor injuries like slipping and falling do not cause miscarriage. However, major injuries like a bad car crash can cause miscarriage.

Causes in the first 12 weeks of pregnancy

  • A problem with the fetus, such as a birth defect or an inherited disorder

Sometimes the fetus has a defect that is so severe that the fetus can't live more than a month or two inside you. A severe defect causes most miscarriages in the first 12 weeks of pregnancy.

Causes in weeks 13 through 20 of pregnancy

Often, doctors never figure out the cause of miscarriage at this stage. But sometimes they can pinpoint one of these as the cause:

Causes of repeated miscarriages

If you have had several miscarriages, doctors will look for problems such as:

  • Blood that clots too easily in the woman

  • Abnormal chromosomes in the fetus from either parent

What are the symptoms of a miscarriage?

A miscarriage early in pregnancy may just seem like a normal period. If you didn't know you were pregnant, you probably wouldn't think you were having a miscarriage.

Other times there are obvious symptoms:

  • Bright or dark red blood

  • Cramping

  • Passing large clots and bits of tissue

At first you may have only a small amount of bleeding, similar to having your period. As the miscarriage continues, the bleeding usually gets worse. The blood may be bright or dark red. Sometimes you'll also pass blood clots. You'll have cramps that may get worse as your uterus (womb) pushes out bits and pieces of the pregnancy.

Call your doctor right away if you have any bleeding during your pregnancy. Not all bleeding during pregnancy means you're having a miscarriage. About half the time, the pregnancy continues just fine. However, your doctor needs to check to see whether you had a miscarriage or not. If you pass large clots or bits of tissue, put them in a container or wrap them in a towel for the doctor to look at.

How can doctors tell if I've had a miscarriage?

If you've had bleeding or cramping during the first 20 weeks of your pregnancy, doctors will:

How do doctors treat a miscarriage?

If the fetus and the placenta (the organ that feeds the fetus) are no longer in your body, you won't need any treatment. The bleeding and cramps will stop soon.

If bits and pieces of the pregnancy are still in your body, doctors might:

  • Watch to see if your uterus will empty itself, as long as you don’t have a fever or seem sick

  • Do a procedure to remove the rest of the pregnancy

If doctors need to remove pieces of your pregnancy from your uterus, they'll give you medicine to make you sleepy. The procedure you have depends on how far along the pregnancy is:

  • In the first 12 weeks of pregnancy: Remove pieces using a suction instrument put into your uterus through your vagina

  • Between 12 and 20 weeks of pregnancy: Remove pieces using surgical instruments put into your uterus through your vagina

  • If close to 20 weeks of pregnancy: You may be given a medicine to start labor to pass the rest of the pregnancy

How can I prevent a miscarriage?

You can't really prevent a miscarriage. If you've had some bleeding or cramping during the first 20 weeks of your pregnancy, your doctor may tell you to avoid too much physical activity and stay off your feet. But there's no proof these things help.

How can I feel better after a miscarriage?

It's normal to feel grief, anger, and guilt after a miscarriage.

  • Consider talking with another person if you feel sad and are grieving your loss

  • If you’re worried about having another miscarriage, talk to a doctor who can discuss possible tests

  • Remember that many women who miscarry get pregnant again and give birth to healthy babies

Drugs Mentioned In This Article

Generic Name Select Brand Names
quiz link

Test your knowledge

Take a Quiz!