What Is Miscarriage?

Miscarriage is the loss of a pregnancy before 20 weeks gestation. If a pregnancy ends with the fetus’s death after 20 weeks gestation, the loss is classified as a stillbirth. Medically, miscarriage is called spontaneous abortion, a name that stems from the fact that the body suddenly ends the pregnancy. 

Although many people don’t talk about miscarriages, they are very common. Ten to 15% of pregnancies where the mother knows that she is pregnant will end in miscarriage. The odds of miscarriage are highest early in pregnancy and decrease with time. However, miscarriage is pervasive: one in four pregnancies end in miscarriage.

Causes of Miscarriage

Most often, miscarriage is caused by chromosomal abnormalities in the fetus that make it unable to develop properly. However, structural causes with a person’s reproductive organs and infection can also cause miscarriage.

Chromosomal Causes of Miscarriage

Problems with the chromosomes of the fetus are the most common cause of miscarriage. This can include:

• The wrong number of chromosomes: In about half of the cases of miscarriage, the embryo has the wrong number of chromosomes, rather than the 23 pairs that healthy individuals need. Sometimes, having too many or too few chromosomes is compatible with life, as with Down syndrome, but oftentimes it will cause the fetus to stop developing in the womb.
• Translocation: This happens when part of one chromosome moves onto another chromosome. There is a genetic factor, so this can explain some repeat miscarriages. 

These chromosomal abnormalities can lead to different types of miscarriage, including:

• Blighted ovum: This is when an embryo is conceived and implants, but does not develop. This occurs extremely early in pregnancy. 
• Intrauterine fetal demise: Similar to a blighted ovum, this is when a fetus starts to develop, then stops, likely because of chromosomal abnormalities. 
• Molar pregnancy: This occurs when tissue forms into a tumor, rather than developing into a healthy fetus. 

Structural Causes of Miscarriage

Some miscarriages are caused by structural abnormalities in the woman carrying the pregnancy. These may need to be addressed to prevent future miscarriages. These can include:

• Uterine fibroids or scars: These can impact the growth of a fetus and may need to be removed surgically. 
• Cervical issues: Also called incompetent cervix, this is when the cervix opens—or dilates—earlier in the pregnancy than normal. If this is detected, your healthcare provider may use a stitch called a cerclage to keep your cervix closed until the pregnancy is viable. 

Infections

Occasionally, infections can cause miscarriage. These can include:

• Sexually transmitted infections: STIs like gonorrhea can increase your risk for miscarriage and other pregnancy complications. 
• Other infections: Routine infections, such as food poisoning caused by listeriosis, can increase risk for miscarriage. 

Risk for Miscarriage

Miscarriage can happen to anyone. Remember, one in four pregnancies will end in miscarriage. However, certain factors put you at a higher risk of having a miscarriage. These include: 

• Age: The risk for miscarriage increases sharply beginning at age 35. Between ages 35 and 40, the risk for miscarriage doubles from 20% to 40%.
• Previous miscarriages: If you have had a previous miscarriage, and especially if you have had two or more, you are at increased risk for future miscarriages.
• Exposure to harmful substances: Being exposed to harmful substances can increase your risk of miscarriage. These include legal substances like cigarettes and alcohol, illegal drugs, and environmental toxins.
• Being overweight: People who are overweight have a slightly higher chance of miscarrying.
• Other health conditions: Some health conditions—like autoimmune diseases—can increase your odds of miscarriage. If you’re worried about how your health might impact pregnancy, talk with your healthcare provider. 

Signs of Miscarriage

The most common sign of miscarriage is bleeding from the vagina during pregnancy. Some people also experience pain or cramps, similar to those that come before or during a menstrual period. If you experience this, reach out to your healthcare provider.

Remember—it’s always better to get checked out when you’re worried than it is to potentially miss a problem with your pregnancy. 

Missed Miscarriage 

A missed miscarriage, also known as a silent miscarriage, is when the fetus stops developing but the body doesn’t begin to get rid of the tissue immediately. That means you don’t experience symptoms like bleeding or cramping. 

With missed miscarriages, a woman will sometimes experience bleeding weeks after the fetus has stopped developing.

Diagnosis

If you are experiencing symptoms of a miscarriage, especially bleeding, your healthcare provider may be able to diagnose the condition based on your reports. However, in many cases medical professionals will order an ultrasound to confirm that the fetus is no longer viable.

After a miscarriage, your practitioner may test the hormone levels in your blood to confirm that the pregnancy hormone is dropping. 

Treatment

In many cases, people who experience miscarriage do not need treatment. However, you can talk to your practitioner about ways to manage the physical pain of miscarriage, which can be substantial. You should also call your healthcare provider if you think that your bleeding is excessive.

Some people, especially those who have a missed miscarriage, may need medical support to ensure that the tissue from the pregnancy is entirely removed from their bodies. Your healthcare provider can do this with medication that induces bleeding, or by a surgery called a dilation and curettage (D&C), which removes tissue from the uterus. 

Recovering After a Miscarriage

After a miscarriage, your period will return once pregnancy hormones have left your system, usually after four to six weeks. In most cases, it’s safe to begin trying to get pregnant again right away, but talk to your healthcare provider about your specific case. 

A small number of people—about 1%—will experience repeat miscarriages. If this happens to you, your practitioner will likely try to identify the cause of the miscarriages and suggest treatments that might improve your chances of carrying a pregnancy to term.

A Word From Verywell

Miscarriage is very common. However, experiencing a miscarriage can be incredibly difficult. The physical pain of miscarrying is just one portion. Processing the loss of a pregnancy and your hopes and dreams for the child that you could have had can be traumatic. 

If you are experiencing complications of a miscarriage—whether physical or emotional—reach out to your healthcare provider. They likely can provide resources to support families through pregnancy loss.

You might also find support from sharing your story with your loved ones. Remember that most people who experience a miscarriage can go on to have a healthy, full-term pregnancy.