Placenta accreta is a condition in which the placenta attaches abnormally deep into the uterine wall, sometimes invading the muscle layer (increta) or even growing through the uterus into adjacent organs (percreta). This spectrum of conditions is most commonly associated with prior cesarean sections and placenta previa. The major risk is severe, life-threatening hemorrhage during delivery when the placenta cannot separate normally. On ultrasound, signs of accreta include loss of the normal clear zone between the placenta and the myometrium, irregular lacunae (vascular spaces) within the placenta giving a “Swiss cheese” appearance, thinning of the myometrium over the placenta, and increased vascularity at the placenta-uterine interface on color Doppler. Prenatal detection allows planned delivery at a specialized center.
Sonography Term