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What Is Miscarriage?
Doctors define miscarriage as the loss of a pregnancy before the 20th week. Miscarriage also may be called early pregnancy loss or by the medical term for a natural pregnancy loss at this stage, spontaneous abortion.
Most miscarriages — up to 80% — occur in the first trimester before the 12th week of pregnancy. Miscarriage in the second trimester, between 13 and 19 weeks, happens in 1% to 5% of pregnancies.
Pregnancy loss that happens after 20 weeks is called stillbirth.
How common is miscarriage?
Miscarriage is the most common type of pregnancy loss. Research suggests that more than 30% of pregnancies end in miscarriage, many times before a person knows they’re pregnant.
Among women who know they’re pregnant, about 10% to 20% of pregnancies end in miscarriage.
What are the types of miscarriages?
The types of miscarriages are:
- Asymptomatic — There's no bleeding or cramping, and no tissue passes out of your body. It's sometimes called an empty sac pregnancy.
- Biochemical — Occurs shortly after implantation. The resulting bleeding occurs around the time of your expected period, so you may not realize you’d conceived. Biochemical miscarriages may account for 50% to 75% of all miscarriages.
- Complete — When your body pushes out all of the tissue from the pregnancy, either suddenly or after having medical treatment.
- Inevitable — When bleeding and cramping symptoms are present, and the cervix (the opening that connects to the uterus at the top of the vagina) is dilated (open).
- Incomplete — When your body doesn't push all of the tissue from pregnancy out of the uterus. Bleeding, contractions, and cramping are signs of incomplete miscarriage.
- Repeat — The loss of two pregnancies in a row. It's also called recurrent pregnancy loss.
- Septic — Any pregnancy loss, spontaneous or induced, that's complicated by infection.
- Threatened — When you have bleeding, little or no pain, and a closed (undilated) cervix. The fetus may show cardiac activity on an ultrasound. Most of the time, threatened miscarriages turn out fine.
What causes miscarriage and repeat miscarriage?
Doctors don’t know what causes every miscarriage, but chromosomal problems are behind up to 70% of all miscarriages.
Chromosome problems that can cause miscarriages in the first 12 weeks include:
- Blighted ovum – When an embryo implants in the body but doesn’t develop into a baby.
- Intrauterine fetal demise — When an embryo stops developing and dies.
- Molar pregnancy — When tissue in the uterus forms a grape-like tumor at the beginning of pregnancy.
- Translocation — When part of a chromosome moves to another chromosome.
Other chromosome issues, such as anencephaly (a type of neural tube defect), trisomies (an extra chromosome that can cause conditions such as Down syndrome), renal agenesis (a type of kidney defect), or hydrops (a type of thalassemia), may also cause miscarriage.
Problems with the uterus or cervix that can cause miscarriage after 12 weeks but before 20 weeks include:
- Septate uterus — When a band of muscle or tissue (septum) divides the uterus into two sections.
- Asherman syndrome — Produces scar tissue in the uterus that can damage the uterine lining (endometrium). Asherman syndrome may often cause repeat miscarriages that happen before you know you’re pregnant.
- Fibroids and polyps or scars from surgery on the uterus — These can interfere with your baby’s blood supply and limit space for a baby to grow.
- Cervical insufficiency (also called incompetent cervix) — When your cervix opens (dilates) too early during pregnancy, usually without pain or contractions.
Infections can also cause miscarriage.
Common infections that can affect pregnancy include:
- Cytomegalovirus (CMV) — A common virus that infects people of all ages.
- Parvovirus B19 — Causes fifth disease, a common childhood illness.
- Listeriosis — A kind of food poisoning.
- Sexually transmitted infections (STIs) — Infections you get from having sex with someone who's infected.
Other possible causes of miscarriage include:
- Abnormal blood clots.
- Placental abruption.
- Premature rupture of the membranes (PROM) — When the amniotic sac around your baby breaks (your water breaks) before labor starts.
- Preterm labor.
What are miscarriage risk factors and complications?
Miscarriage risk factors
You may be at greater risk of miscarriage if you:
- Have had two or more previous miscarriages.
- Are older. As you age, your risk of having a miscarriage increases. For women over age 40, about one in three pregnancies end in miscarriage. Your partner's age may also increase your risk of miscarriage.
- Smoke, drink alcohol, or use street drugs.
- Have had exposure to harmful chemicals.
Some health conditions may also increase your risk of miscarriage. Treatment of these conditions before and during pregnancy can sometimes help prevent miscarriage and repeat miscarriages.
These health issues include:
- Autoimmune disorders, such as antiphospholipid syndrome and systemic lupus erythematosus (lupus or SLE).
- Congenital heart disease.
- Group B beta strep infection.
- Hormone problems, such as polycystic ovary syndrome (PCOS) and luteal phase defect.
- Obesity. Defined as a body mass index (BMI) of 30 or higher. BMI is a measure of body fat based on your height and weight. Calculate your BMI with our Health Library.
- Preexisting diabetes.
- Preexisting high blood pressure.
- Thyroid problems.
- Severe kidney disease.
- Severe malnutrition.
Other factors that may increase your risk of miscarriage include:
- Certain prenatal tests — Amniocentesis and chorionic villus sampling have a slight risk of causing a miscarriage.
- Certain medications — Some research has shown that nonsteroidal anti-inflammatory medications (NSAIDs) like ibuprofen, naproxen, and diclofenac may increase miscarriage risk. The acne medicine isotretinoin has also been linked to miscarriage and fetal abnormalities.
- Getting pregnant with an intrauterine device (IUD) in place — Rarely, you can pregnant using an IUD (a contraception device placed in your vagina).
- Stress — Both short-term and long-term stress increases your risk of miscarriage.
- Socioeconomic status and other social determinants of health — Racial, ethnic, and financial inequities, compounded by the risk of violence, homelessness, and food insecurity can negatively affect your health. These factors increase your risk of developing other serious and chronic health conditions that can increase your chances of miscarriage.
What doesn’t cause miscarriage:
- Exercising.
- Falling on your belly or getting hit in the abdomen. Your body does a good job of protecting your baby in the early weeks of pregnancy.
- Having sex.
- Too much caffeine. Not enough research has been done to understand caffeine’s effects on pregnancy. For that reason, it’s best to limit the amount you get to 200 mg per day, or about one 12-ounce cup of coffee.
Complications of miscarriage
Complications of miscarriage are rare, but may include:
- Infection (septic) abortion — When tissue from the placenta or fetus remains in the uterus after miscarriage, causing fever, vaginal bleeding, cramping, and discharge with a foul odor. Seek medical help right away if you suspect an infection, as they septic abortions are serious and life-threatening.
- Depression — Although your body may recover quickly from miscarriage, it may take you longer to recover emotionally. No matter how far along the pregnancy was, it’s natural for you to have strong feelings of grief over the loss of your baby. Grief can make you feel angry, alone, confused, and sad.
It's important to take time to grieve after a miscarriage. Ask your family and friends for support. Also, talk to your doctor about support groups or mental health services that can help you with recovery from grief.
Learn more about pregnancy and infant loss services.
How can I prevent miscarriage?
Miscarriages usually can’t be prevented, but being healthy before pregnancy can help prevent pregnancy complications.
Before you get pregnant:
- Get a pre-pregnancy checkup.
- Tell your provider about any health conditions that might affect your pregnancy.
- Take folic acid to help prevent birth defects.
- Eat a healthy diet full of nutrients.
- Get to or maintain a healthy weight.
- Exercise for both a mental and physical boost.
Having optimal pre-pregnancy health can help prevent birth defects and improve your odds of a healthy pregnancy.
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What Are the Signs and Symptoms of Miscarriage?
If you're experiencing symptoms of a miscarriage, call your doctor immediately.
Signs and symptoms of miscarriage include:
- Back pain.
- Cramping, like strong period cramps.
- Contractions or abdominal tightness that comes and goes.
- Fever.
- No longer feeling pregnant, such as not feeling the baby move or not having breast tenderness.
- Passing clumps of tissue from the vagina.
- Strong abdominal pain.
- Vaginal discharge with a bad smell.
- Vaginal spotting or light bleeding that progresses to heavier bleeding.
Many people experience some of these signs and symptoms in early pregnancy and don’t have a miscarriage.
When should I see a doctor about my miscarriage symptoms?
If you think you could be having a miscarriage, call your doctor. Miscarriages can be dangerous if they’re not treated.
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How Do You Diagnose Miscarriage?
Your ob-gyn also may do a pelvic exam to see if your cervix has begun to dilate (open). Dilation of the cervix means that a miscarriage is more likely.
They'll also likely run tests.
If they're unable to confirm the miscarriage, your doctor may recommend:
- Bed rest.
- Bloodwork to check the amount of HCG, or pregnancy hormone, in your system.
- Genetic tests.
- Hospitalization.
- Medical procedures, such as a surgical procedure to treat incompetent cervix.
Tests to diagnose miscarriage
If they suspect you're miscarrying, your ob-gyn may order:
- Ultrasound — If you're bleeding and cramping, an ultrasound will show if the pregnancy is growing normally and may detect cardiac activity if the pregnancy is far enough along. If cardiac activity isn't detected, it may be too early in the pregnancy, or it the embryo may have stopped developing.
- Blood tests — You also may have a blood test to measure human chorionic gonadotropin (hCG), which is the substance detected in pregnancy tests. A low or decreasing level of hCG can mean pregnancy loss.
Several ultrasounds and hCG tests may be needed to confirm miscarriage.
Miscarriage prognosis
Most people who miscarry go on to have a healthy pregnancy later.
However:
- About 1% of pregnant people have a repeat miscarriage.
- The risk of a second miscarriage is 20%.
- After two miscarriages in a row, the risk of another miscarriage increases to about 28%.
- After three or more miscarriages in a row, the risk of having another miscarriage is about 43%.
If you suffer from repeated miscarriages (more than two miscarriages in a row), your doctor may recommend diagnostic procedures to determine the cause, including:
- Blood tests to detect clotting disorders called thrombophelias.
- Endometrial biopsy, during which a small amount of tissue is removed from the lining of the uterus.
- Hysteroscopy, a test that allows the physician to see inside the uterus using a small telescope-like device.
- Laparoscopy, a surgical procedure that uses a lighted device to allow the physician to see your pelvic organs.
- X-rays of the uterus and fallopian tubes
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How Do You Treat Miscarriage?
Treatment for miscarriage depends on how far along you were in your pregnancy, your overall health, your age, and other factors.
If it's a complete miscarriage, meaning there's no remaining fetal or placental tissue in your uterus, no further treatment is required.
Medicine to treat miscarriage
Your doctor may prescribe medication to help your body completely expel the contents of your uterus.
Surgery for miscarriage
If the uterus doesn't empty completely on its own, your doctor may perform a procedure to remove the leftover tissues to prevent serious complications.
Procedures include:
- Dilation and curettage (D&C) — Widens your cervix and uses an instrument called a curette to remove any remaining tissue and the lining of the uterus.
- Dilation and evacuation (D&E) — Widens your cervix and removes any remaining tissue from the uterus using suction.
What happens to my body after a miscarriage?
After miscarriage, it can take a few weeks to a few months for your body to recover. Depending on how far along the pregnancy was, you may still have pregnancy hormones in your bloodstream for one to two months after you miscarry. Most women get their period again four to six weeks after a pregnancy loss.
When can I try to get pregnant again after miscarriage?
Most doctors say you can try to get pregnant again after you’ve had at least one normal menstrual period. However, you may not be emotionally ready to try again right away.
If you’re having medical tests to try to find out more about why you miscarried, you may need to wait until after you’ve had these tests to try to get pregnant again.
Miscarriage can be emotional and sad, and you and your partner may need time to grieve. It’s OK if you want to wait a while before trying to get pregnant again.
If you're trying to conceive, start taking a prenatal vitamin with at least 400mcg of folic acid now — even if you don’t get pregnant right away. The folic acid helps prevent neural tube defects in the very early stages of pregnancy.
Last reviewed by a UPMC medical professional on 2024-09-05.
