A: Placenta accreta occurs when your placenta implants too firmly and deeply in the uterine wall, which can cause premature birth or serious bleeding after a vaginal delivery. (Placenta accreta should not be confused with placenta increta, where it attaches more deeply, or placenta percreta, in which the placenta breaks through the uterine wall, occasionally touching nearby organs.)
Women who've had placenta previa (where the placenta covers all or part of the opening of the cervix) or uterine surgery (like a previous c-section or treatment for endometriosis) are most at risk for developing placenta accreta. The most common symptom is bleeding in the third trimester.
Placenta accreta is usually diagnosed by an ultrasound, and if it is discovered, you'll probably deliver via c-section. Performing a c-section minimizes the risk of heavy bleeding and allows your doctor to ensure that the placenta is removed completely after delivery. In very rare cases, the uterus can be so badly damaged that a hysterectomy is needed, but the majority of placenta accreta cases result in totally healthy moms and babies.