The document discusses retained placenta, which is defined as the placenta remaining in the uterus for more than 30 minutes after delivery. Signs of placental separation are listed. Management of retained placenta includes ensuring an empty bladder, injecting oxytocin or other substances into the umbilical cord, and manually removing the placenta while massaging the uterus. Complications like placenta accreta can cause extensive attachment making manual removal difficult and potentially requiring uterine artery ligation or hysterectomy. Ultrasound may help identify accreta cases.