Placenta previa (pluh-SEN-tuh PREH-vee-uh) occurs when a baby's placenta partially or totally covers the opening in the mother's cervix — the lower end of the uterus that connects to the top of the vagina. Placenta previa can cause severe bleeding before or during delivery.
The placenta provides oxygen and nutrients to your growing baby and removes waste products from your baby's blood. It attaches to the wall of your uterus, and your baby's umbilical cord arises from it. In most pregnancies, the placenta attaches at the top or side of the uterus. In placenta previa, the placenta attaches to the lower area of the uterus.
If you have placenta previa, you'll probably be restricted from physical exertion for a portion of your pregnancy and you'll likely require a cesarean section (C-section) to safely deliver your baby.