Abstract: Uterine atony is the most common cause of postpartum hemorrhage. Common high-risk early-warning indicators include：bleeding volume，blood loss rate，vital signs，shock index and fibrinogen level. Based on early-warning indicators，plans should be made in advance. Rescue measures must reflect "initiative"，and early intervention can avoid adverse consequences.

Key words: vaginal delivery, uterine atony, postpartum hemorrhage, early warning, invasive method

摘要： 子宫收缩乏力是最常见的产后出血原因，常用高危预警指标包括：出血量、失血速度、生命体征、休克指数以及纤维蛋白原水平，基于预警指标应提前做好预案，抢救措施一定要体现“主动性”，早期干预才能避免不良后果发生。

关键词: 阴道分娩, 子宫收缩乏力, 产后出血, 预警, 侵入性方法