The placenta forms during pregnancy. It gives the baby nutrients and oxygen. It also removes waste products. Normally, the placenta attaches to the inner wall of the uterus, away from the opening of the uterus. Sometimes the placenta attaches so low that it blocks part of the opening. This is called placenta previa.
Bed rest has not been shown to help prevent problems in most women with placenta previa. But your doctor may recommend that you limit your activities. Your doctor will watch you closely until your baby can be safely delivered.