Placenta previa

ARTICLE SECTIONS

Definition

Placenta previa is an uncommon pregnancy complication that can cause excessive bleeding before or during delivery.

Soon after conception, the placenta begins to form. This circular, flat organ provides oxygen and nutrients to your growing baby and removes waste products from your baby's blood. It attaches both to the wall of your uterus and to your baby's umbilical cord, forming a vital connection between you and your baby.

Early in pregnancy, the placenta may implant in the lower part of the uterus. As the uterus grows, the placenta usually moves up and away from the opening of the uterus (cervix). If it doesn't, the cervix may be blocked. This is known as placenta previa.

If you have placenta previa, the placenta will detach from the lower part of the uterus as the cervix begins to open in preparation for labor. This can cause severe vaginal bleeding. Thankfully, placenta previa is nearly always detected before a woman or her baby is in significant danger.

Symptoms