The third stage of labor occurs after the baby has been delivered, and involves delivery of the placenta.

第三产程在胎儿已经娩出后发生，即胎盘的娩出。

The entire placenta normally separates from the uterine wall in the third stage of labor, but occasionally a part of the placenta remains behind in the uterus.

正常情况下，胎盘组织会在第三产程中从子宫壁上完整的脱落并娩出，但在某些情况下，部分胎盘组织将在术后残留在子宫腔内无法自行排出。