Pregnancy Loss (Before 20 Weeks of Pregnancy)

Pregnancy loss is the unexpected loss of a fetus before the 20th week of pregnancy. It is sometimes called miscarriage, early pregnancy loss, mid-trimester pregnancy loss, fetal demise, or spontaneous abortion.

Health care providers use a different term—stillbirth—to describe the loss of a fetus after 20 weeks of pregnancy.

Pregnancy loss may occur so early that a woman may not know she was pregnant.¹

Researchers can only estimate the number of women who experience pregnancy loss, because some losses occur before a woman's pregnancy is confirmed by a health care provider or pregnancy test. But the American College of Obstetricians and Gynecologists estimates that early pregnancy loss is common, occurring in about 10% of confirmed pregnancies.²

Symptoms of pregnancy loss may include:

• Bleeding from the vagina
• Pain or cramps in the lower stomach area (abdomen)
• Low back pain
• Fluid, tissue, or clot-like material coming out of the vagina

However, bleeding from the vagina during pregnancy doesn't always mean a miscarriage. Many pregnant women have spotting and cramping in early pregnancy but do not miscarry.¹ Your health care provider might call this pregnancy "threatened."2 In any case, pregnant women who have any of the symptoms of miscarriage should contact their health care provider immediately.²

Some women do not experience any symptoms of pregnancy loss.

Although this is rare in the United States, some women who have a miscarriage may get an infection in the uterus, which can be life threatening. Women who have the following symptoms more than 24 hours after a should call 911:³

• A fever higher than 100.4 degrees Fahrenheit on more than two occasions
• Severe pain in the lower abdomen
• Bloody discharge from the vagina (which can include pus and be foul smelling)

Recent research has also found that morning sickness—nausea and vomiting during pregnancy—is linked to lower risk of pregnancy loss. NICHD researchers are continuing to look for other factors that may indicate lower risk of pregnancy loss.

Pregnancy loss may occur for many reasons, and sometimes the cause remains unknown even after additional tests are completed.

Possible Causes

Pregnancy loss often happens when a pregnancy doesn't develop normally.

In many cases, miscarriages result from a problem with the chromosomes in the fetus.¹ The number of chromosomes the fetus has—too many or too few—can affect survival.

Other possible causes of pregnancy loss include:

• Being exposed to toxins in the environment
• Problems of the placenta, cervix, or uterus²
• Problems with the father's sperm²

In many cases, though, health care providers can't identify a cause or causes for pregnancy loss.

Risk Factors

Problems with chromosomes happen more often in the fetuses of older parents, particularly among women who are older than 35.¹ For this reason, risk for pregnancy loss increases as the parents age; it is much higher at age 45 than at age 35.¹

Women who have had previous miscarriages are also at a higher risk for pregnancy loss.²

Health issues, such as chronic diseases, in the mother that can also increase risk for pregnancy loss include:

• Chronic diseases, such as high blood pressure, diabetes, thyroid disease, or polycystic ovary syndrome (PCOS)
• Problems with the immune system, such as an autoimmune disorder
• Infections (such as untreated gonorrhea or Zika)
• Hormone problems
• Extremes in weight, such as obesity or being too thin
• Lifestyle factors, such as using drugs³ or alcohol,⁴ smoking,⁵ or consuming more than 200 milligrams of caffeine per day (equal to about one 12-ounce cup of coffee)^6,7

Findings from an NICHD study suggest that women who are at higher risk for pregnancy loss because of two or more previous losses may increase their chances of carrying the pregnancy to term by taking a low-dose aspirin every day if they have high levels of inflammation.

Recent research has also found that morning sickness—nausea and vomiting during pregnancy—is linked to lower risk of pregnancy loss. NICHD researchers are continuing their research to find other factors that may indicate lower risk of pregnancy loss.

If a pregnant woman has any of the symptoms of pregnancy loss, such as abdominal cramps, back pain, light spotting, or bleeding, she should contact her health care provider immediately. Remember that vaginal bleeding during pregnancy does not definitely mean a pregnancy loss is occurring.

Diagnosing Pregnancy Loss

Depending on how far along the pregnancy is, health care providers may use different methods to determine whether a pregnancy loss has occurred:

• A blood test to check the level of human chorionic gonadotropin (hCG), the pregnancy hormone
• A pelvic exam to see whether the woman's cervix is dilated or thinned, which can be a sign of pregnancy loss
• An ultrasound test, which allows the provider to look at the pregnancy, uterus, and placenta1¹

If a woman has had more than one miscarriage, she may want to have a health care provider check her blood for chromosome problems, hormone problems, or immune system disorders that may be contributing to pregnancy loss.²

Treating Pregnancy Loss

Treatments for pregnancy loss focus on ensuring that the nonviable pregnancy leaves the woman's body safely and completely. Women going through pregnancy loss are at risk for bleeding, pain, and infection, especially if some of the pregnancy tissue remains behind in the uterus.

The specific treatment used depends on how far along the pregnancy was, the woman's overall health, her age, and other factors.¹

In many cases, pregnancy loss before 20 weeks may not require any special treatment. The bleeding that occurs with pregnancy loss empties the uterus without any further problems.

Women who have heavy bleeding during pregnancy loss should contact a health care provider immediately. For reference, heavy bleeding refers to soaking at least two maxi pads an hour for at least 2 hours in a row.¹

Some women may need a surgical procedure called a dilation and curettage (D&C) to remove any pregnancy tissue that is still in the uterus. A D&C is recommended if a woman is bleeding heavily or if an ultrasound shows pregnancy tissue is still in the uterus. D&C may also be used if a woman has any signs of infection, such as a fever, or if she has other health problems, such as cardiovascular disease or a bleeding disorder.¹

Some women are treated with a medication called misoprostol, which helps the tissue pass out of the uterus and controls the resulting bleeding. Research shows that misoprostol is safe and effective in most cases.^1,3

Women who lose a pregnancy may also need other treatments to control mild to moderate bleeding, prevent infection, relieve pain, and help with emotional support.

Although this is rare in the United States, some women who have a miscarriage may get an infection in the uterus, which can be life threatening. Women who have the following symptoms more than 24 hours after treatment should call 911:⁴

• A fever higher than 100.4 degrees Fahrenheit on more than two occasions
• Severe pain in the lower abdomen
• Bloody discharge from the vagina that includes pus or is foul smelling

There is currently no known way to prevent pregnancy loss before 20 weeks from occurring, nor is there a way to stop pregnancy loss once it has started.

There are ways to lower the risk of general pregnancy complications, but none of them definitely prevent pregnancy loss. Some ways to lower overall risk include:

• Staying in good health before becoming pregnant and getting regular care during pregnancy
• Diagnosing any health conditions, such as diabetes or thyroid disorders, and taking steps to manage or treat the condition before getting pregnant
• Avoiding environmental hazards, such as exposure to radiation, pollution, or toxic chemicals
• Avoiding alcohol and drugs, including high levels of caffeine in both partners
• Protecting yourself from certain infections by not traveling to certain areas and by preventing mosquito bites¹

An NICHD study found that women who are at higher risk for pregnancy loss because of two or more previous losses may increase their chances of carrying the pregnancy to term by taking a low-dose aspirin every day if they have high levels of inflammation.