Some pregnant women have some vaginal bleeding, with or without abdominal cramps, during the first three 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 medical abortions or surgical abortions.)
Miscarriage occurs in about half of pregnancies with first trimester bleeding.
You may be told to avoid or restrict some forms of activity. Not having sexual intercourse is usually recommended until the warning signs have disappeared.
The use of progesterone is controversial. It might relax smooth muscles, including the muscles of the uterus. However, it also might increase the risk of an incomplete abortion or an abnormal pregnancy. Unless there is a luteal phase defect, progesterone should not be used.
Many women with threatened miscarriage go on to have a normal pregnancy.
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 immediately.
Some studies show that women who get prenatal care have better pregnancy outcomes, for themselves and their babies. Miscarriages are less likely if you receive early, comprehensive prenatal care and avoid environmental hazards such as x-rays, drugs and alcohol, high levels of caffeine, and infectious diseases.
It is better to find and treat health problems before you get pregnant than to wait until you're already pregnant. Many miscarriages that are caused by body-wide (systemic) diseases that can be prevented by detecting and treating the disease before becoming pregnant. Being obese or having uncontrolled diabetes can increase your risk for miscarriage.
American College of Obstetricians and Gynecologists. ACOG Committee opinion no. 462: Moderate caffeine consumption during pregnancy. Obstet Gynecol.2010 Aug;116(2 Pt 1):467-8.
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.
Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.