Hemorrhage into the decidua basalis, formed retroplacental hematoma, lead to the separationof the placenta.
出血进入蜕膜基底，形成胎盘后血肿，导致胎盘分离。
2
Methods All 135 patients had spontaneous delivery at term. The placentaseparation was categorized during the third stage labor with ultrasonographic imaging, and quantity of bleeding measured.
方法对135例单胎自然分娩的胎盘剥离声像图进行分类，并采用称重法测量第三产程出血量。
3
Objective To observe the mode ofplacentaseparation by dynamic ultrasonographic imaging during the third stage of labor and help manage postpartum hemorrhage.