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The reasons for vaginal bleeding during pregnancy

Fortunately, most women who experience vaginal bleeding or spotting during pregnancy go on to have healthy babies. Early in pregnancy, light bleeding may occur when the fertilized egg attaches itself to the uterine wall. Hormonal changes at the time a woman would normally be menstruating can also cause spotting.

If you’re bleeding lightly and have no other symptoms, your healthcare provider may advise bed rest until 48 hours after the bleeding has stopped. Heavier bleeding or bleeding accompanied by other symptoms may indicate a serious situation, such as:

    Miscarriage. At least 20 percent of pregnancies end spontaneously. The most common symptoms are heavy bleeding and abdominal cramps. Sometimes tissue fragments (grayish matter) are passed with the blood. A dilation and curettage (D&C, or scraping of the uterus) may be performed to prevent excess blood loss.

    Ectopic pregnancy. This is a pregnancy that occurs outside the uterus, usually in a fallopian tube. Symptoms include brown vaginal spotting, cramps, nausea, dizziness, weakness, shoulder pain and/or rectal pressure. In some cases, the fertilized egg is surgically removed.

    Placenta previa. In about one in 200 pregnancies, the placenta grows too low in the uterus, partially or completely covering the cervix. This may cause bleeding, the only symptom, later in pregnancy—usually after 30 weeks—and make vaginal delivery impossible. Bed rest is usually recommended to prevent excessive bleeding.

    Placental abruption. In this condition, the placenta tears away from the uterine wall. About half the time this happens after 36 weeks, when the baby can be safely delivered by cesarean section. Symptoms include vaginal bleeding and severe abdominal pain.

    Premature labor. When labor begins before the 37th week, it’s considered premature. The passage of a thick mucus plug followed by a pinkish or brownish bloody discharge may signal the start of labor. Other signs include cramps, diarrhea, nausea, fluid leakage, lower-back pain and achiness in the groin. Tell your healthcare provider immediately about the signs of premature labor because treatment can sometimes postpone labor until the baby is closer to term.