A threatened miscarriage is a condition that suggests a miscarriage might take place before the 20th week of pregnancy.
Some pregnant women have some vaginal bleeding, with or without abdominal cramps, during the first 3 months of pregnancy. When the symptoms indicate a miscarriage is possible, the condition is called a "threatened abortion." (This refers to a naturally occurring event, not to medical abortions or surgical abortions.)
Miscarriage is common. It occurs in up to 40 out of every 100 pregnancies. The chance of miscarriage is higher in older women. About half of women who have bleeding in the first trimester will have a miscarriage.
Symptoms of a threatened miscarriage include:
- Abdominal cramps, with or without vaginal bleeding
- Vaginal bleeding during the first 20 weeks of pregnancy (last menstrual period was less than 20 weeks ago)
Note: During a miscarriage, low back pain or abdominal pain (dull to sharp, constant to intermittent) can occur. Tissue or clot-like material may pass from the vagina.
Exams and Tests
Abdominal or vaginal ultrasound may be done to check the baby's development and heartbeat, and the amount of bleeding. A pelvic exam will be done to check your cervix.
The following blood tests may be done:
You may be told to avoid or restrict some activities. Not having sexual intercourse is usually recommended until the warning signs have disappeared.
Most women with a threatened miscarriage go on to have a normal pregnancy.
Women who have had two or more miscarriages in a row are more likely than other women to miscarry again.
These complications may occur with a threatened miscarriage:
- Anemia from moderate to heavy blood loss, which occasionally requires a blood transfusion
When to Contact a Medical Professional
If you know you are (or are likely to be) pregnant and you have any symptoms of threatened miscarriage, contact your prenatal health care provider right away.
Most miscarriages cannot be prevented. Studies have shown that women who get prenatal care have better pregnancy outcomes for themselves and their babies.
A healthy pregnancy is more likely when you avoid things that are harmful to your pregnancy, such as:
- Infectious diseases
- High caffeine intake
- Recreational drugs
Taking a prenatal vitamin or folic acid supplement before becoming pregnant and throughout your pregnancy can lower your chance of miscarriage.
It is better to treat health problems before you get pregnant than to wait until you are already pregnant. Miscarriages caused by diseases that affect your whole body, such as high blood pressure, are rare. But you can prevent these miscarriages by detecting and treating the disease before becoming pregnant.
Other factors that can increase your risk of miscarriage include:
- Thyroid problems
- Uncontrolled diabetes
Threatened miscarriage; Threatened spontaneous abortion; Abortion - threatened; Threatened abortion
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Cunnigham FG, Leveno KL, Bloom SL, et al. Abortion. In: Cunnigham FG, Leveno KL, Bloom SL, et al, eds. Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010:chap 9.
Gaskins AJ, Rich-Edwards JW, Hauser R, et al. Maternal prepregnancy folate intake and risk of spontaneous abortion and stillbirth. Obstet Gynecol. 2014 Jul;124(1): 23-31.
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Update Date 11/14/2014
Updated by: Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.