Whether to manage placenta previa percreta surgically or conservatively has been a controversial issue. A 30-year-old woman with placenta percreta with bladder involvement was treated conservatively. A planned cesarean section was performed at 33 weeks' gestation. A 1768-g female infant was delivered through a transverse fundal uterine incision with the placenta left inside the uterus. The following morning, a massive postpartum hemorrhage occurred, and was successfully treated with transarterial embolization. The placenta was never expelled and spontaneously disappeared 4 months after surgery. We demonstrate serial magnetic resonance imaging of the placenta percreta during pregnancy and the postpartum period.