What is a miscarriage?

Miscarriage is a pregnancy loss in the first 20 weeks of pregnancy. About 10% to 20% of pregnancies end in miscarriage. This occurs most often in the first trimester (first 13 weeks of pregnancy). From conception to the eighth week of pregnancy, the developing baby is called an embryo. After the eighth week of pregnancy, the baby is called a fetus.

There are different types of miscarriage. These include: 

  • Threatened. Spotting or bleeding in the first trimester may or may not mean a miscarriage will occur. 

  • Complete. The embryo or fetus, placenta, and other tissues are passed with bleeding.

  • Incomplete. Only a part of the tissues passes. Some tissue stays in the uterus. There may be heavy vaginal bleeding.

  • Missed. The embryo or fetus dies, but doesn't pass out of the uterus. Sometimes dark brown spotting occurs. There is no fetal heartbeat or fetal growth.

  • Septic. This is a miscarriage that becomes infected. The pregnant person has a fever and may have bleeding and discharge with a bad odor. Belly (abdominal) pain is common. This is a serious problem. It can cause shock and organ failure if not treated.

  • Recurrent. When a person has 3 or more miscarriages.

What causes a miscarriage?

About half of early pregnancy losses are from chromosome defects in the embryo or fetus. Other causes may include:

  • Abnormal embryo development

  • Hormone problems in the pregnant person. These include low levels of progesterone or a thyroid problem.

  • Diabetes in the pregnant person, especially poorly controlled blood sugar

  • Problems in the uterus. These include scar tissue inside the uterus, abnormally shaped uterus, or fibroids.

  • Opening of the uterus can't stay closed during pregnancy (incompetent cervix)

  • Infection from germs. These include cytomegalovirus (CMV), mycoplasma, chlamydia, listeria, and toxoplasma.

  • Autoimmune diseases such as lupus, in which the body attacks its own tissue 

  • Injury (trauma) 

  • Exposure to toxic substances and chemicals, such as anticancer drugs

Often, the cause of a miscarriage can’t be found. 

Who is at risk for miscarriage?

Some things can make miscarriage more likely. They include:

  • Being pregnant at an older age

  • Having a past early pregnancy loss

  • Smoking cigarettes

  • Drinking alcohol

  • Drinking more caffeine

  • Using cocaine

  • Having a low folate level. Folate is a B vitamin.

  • Taking NSAIDs (nonsteroidal anti-inflammatory drugs) around the time of conception

  • Having a problem with the uterus such as fibroids. Fibroids are noncancerous growths in the uterus. Another problem might be a septate uterus. This is a condition present at birth where tissue divides the uterus.

  • Having certain conditions such as celiac disease, high blood pressure, thyroid disease, or diabetes

  • Having a serious infection or major injury

What are the symptoms of a miscarriage?

The most common symptom of a miscarriage is vaginal bleeding. The bleeding may be painless. Or you may have mild to severe back pain or belly cramping. Some people may pass pregnancy tissue. 

How is a miscarriage diagnosed?

Spotting or small amounts of bleeding during the first trimester is common. This may or may not mean you are having a miscarriage. Your healthcare provider will likely use ultrasound to diagnose miscarriage. If the fetus is no longer in the uterus, or there is no longer a heartbeat, your provider will diagnose a miscarriage. Other tests include blood tests for the hormone human chorionic gonadotropin (hCG). Lower than normal levels of this hormone or levels that don't go up may mean the pregnancy is not growing properly.

How is a miscarriage treated?

If you have vaginal bleeding, but the lab tests and ultrasound show that the pregnancy is OK, your healthcare provider may tell you to rest for a few days. You'll be watched for more bleeding. You may have more hCG blood tests and ultrasound exams to check the growth of the fetus and the fetal heartbeat. 

If tests show that you have had a miscarriage in the first trimester, you may have a few choices. Talk with your provider about the treatment that's best for you. Treatment choices include:

  • Expectant management. This means waiting to let the miscarriage happen on its own. You'll be checked often during this time.

  • Medical management. This is treatment with medicines to help the pregnancy tissues pass. You may get a medicine called misoprostol. It makes the uterus contract and push out the pregnancy tissues.

  • Surgical management. You may need surgery to remove the fetus and other tissues if they haven't all been naturally passed. The procedure is called a surgical evacuation of the uterus, or a dilation and curettage (D&C). You're given anesthesia because the procedure can be painful. The cervical opening is stretched open (dilated). The provider uses either suction or a tool called a curette to remove all the pregnancy tissues inside the uterus.

Pregnancy tissues may be sent to the lab to test for gene or chromosome defects.

If you have an infection, your provider will give you antibiotics.

Pregnancy loss after 20 weeks may need different procedures. You may get medicines such as misoprostol or prostaglandin. These medicines help open the cervix. They make the uterus contract and push out the fetus and tissues. 

What are the complications of a miscarriage?

A miscarriage is a significant loss to the pregnant person and their family. It is appropriate and normal to grieve because of the loss.

Pregnancy loss doesn't often cause other serious health problems unless you have an infection or the tissues aren't passed. A serious complication with a miscarriage after 20 weeks is a severe blood clotting problem. This is more likely if it takes a long time (usually 1 month or more) to pass the fetus and other tissues.

People with Rh negative blood may need treatment after a miscarriage to prevent problems with blood incompatibility in a future pregnancy. A medicine called Rh immunoglobulin may be given.

When should I call my healthcare provider?

Tell your healthcare provider if you have any bleeding during your pregnancy. If you also have other symptoms, such as severe cramping, see your provider as soon as possible. 

Key points about miscarriage

  • Miscarriage is a pregnancy loss in the first 20 weeks of pregnancy.

  • Bleeding in pregnancy may or may not be a sign of a miscarriage.

  • If you have bleeding and other symptoms such as severe cramping, see your healthcare provider as soon as possible. 

  • If you have a miscarriage, you may need a procedure to remove the fetus and other tissues, if they haven't all been naturally passed.

  • If a miscarriage hasn't occurred, you'll likely be told to rest. You and your baby will both be monitored.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

  • Know why a new medicine or treatment is prescribedes and how it will help you. Also know what the side effects are.

  • Ask if your condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if you do not take the medicine or have the test or procedure.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your provider if you have questions.

Online Medical Reviewer: Donna Freeborn PhD CNM FNP
Online Medical Reviewer: Heather M Trevino BSN RNC
Online Medical Reviewer: Irina Burd MD PhD
Date Last Reviewed: 3/1/2022
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