How much do you know about the placenta? If you’re like most people, probably not much. But for the millions of women in the US who become pregnant each year, the placenta becomes a very interesting organ.
The placenta forms during pregnancy and serves as the life support system for a growing baby. It supplies the baby with oxygen, nutrients, and hormones, removes waste products through the umbilical cord, and is vital for a healthy pregnancy and delivery. In some pregnancies, problems with the placenta occur that can endanger mother and baby.
You may have recently heard about placenta previa, a condition that threatened actress Tori Spelling’s fourth pregnancy. Roughly 1 in 200 pregnant women will experience this potentially serious complication. Blood vessels attach the placenta to the uterus. In women with placenta previa, the placenta lies low in the uterus and may partially or completely cover the cervix, blocking the baby’s exit from the uterus. Placenta previa can also cause excessive bleeding in the mother when the cervix begins to thin and open in preparation for delivery. The risk of developing placenta previa is higher in women who’ve had more than one child, a cesarean delivery, surgery on the uterus, or who are carrying twins or triplets.
Roughly 1% of women will experience placental abruption—the detachment of the placenta from the uterus before or during birth. Placental abruption deprives the baby of oxygen and can cause the mother to lose large amounts of blood. Symptoms may include vaginal bleeding and severe abdominal or back pain. Placental abruption usually occurs in the last 12 weeks of pregnancy and is more common among women who have high blood pressure, smoke, or use cocaine or amphetamines during pregnancy. Women who’ve had a previous placental abruption, have had children, are older than 35, or have sickle cell disease are at higher risk.
Placenta accreta occurs when the blood vessels that attach the placenta grow too far into the uterine wall. The condition can cause bleeding during the third trimester of pregnancy and severe, life-threatening blood loss during delivery. Previous cesarean delivery is the main risk factor for placenta accreta, and the risk increases with each cesarean a woman has had.
If you experience bleeding during pregnancy, talk to your doctor right away. It may be related to a placental problem that requires prompt treatment. Learn more about placenta problems during pregnancy.