Dangers for a Mother With Placenta Previa

Placenta previa is a complication that can occur in the last half of pregnancy when the placenta, which is the organ that works with the umbilical cord to nourish the baby in utero, completely or partially covers the cervix instead of moving to the upper part of the growing uterus. As the baby grows and as the cervix begins to open in preparation for birth, pressure on the low-lying placenta can cause significant, life-threatening bleeding. According to Medline Plus, placenta previa affects only one in every 200 births, and is usually discovered before the mother and baby are in jeopardy.

Bleeding Risk

• Women with placenta previa typically notice painless vaginal bleeding at the end of the second trimester or beginning of the third trimester. The blood will be bright red, and the bleeding may be heavy or light, stopping and starting spontaneously over a period of days. Some women experience contractions that accompany the bleeding, and others do not bleed at all from placenta previa until labor starts. If the bleeding is heavy, labor may start within a few days. In addition to an increased risk for infection or blood clots, severe bleeding can cause the mother to go into shock or die from hemorrhaging.

Premature Delivery Risk

• Your doctor may order extra rest to reduce placenta previa risk.

  Cesarean sections are recommended for mothers with diagnosed placenta previa to give the obstetrician more control of the birth. Bed rest or hospitalization may be indicated to try to prevent delivery before 36 weeks' gestation, but an emergency cesarean section may be necessary earlier if the bleeding from placenta previa cannot be controlled or stopped. Placenta previa also can cause the placenta to detach too soon from the uterine wall during labor, which increases bleeding and compromises the infant's blood supply. A baby delivered early usually requires specialized care because of premature lung development and other complications. Maternal blood loss because of the surgery and the placenta previa can require blood transfusions. Infection also is a significant concern.

Placenta Accreta Risk

• According to the American Pregnancy Association, placenta accreta occurs in up to 10 percent of the women who have placenta previa. Diagnosed in only one in 2,500 pregnant women, placenta accreta occurs when the placenta imbeds itself so deeply in the uterine wall that it does not spontaneously release following birth. Efforts to manually detach the placenta can cause life-threatening bleeding, which can only be stopped by an emergency hysterectomy.