Pathophysiologic changes associated with severe placental abruption include uterine changes, such as uteroplacental stroke, and systemic changes, such as coagulation abnormalities. 1. Changes in the uterus: when the bleeding between the placenta and the uterine wall increases, the pressure also increases, and the blood invades the myometrium, causing the muscle fibers to separate, break and even degenerate. When blood invades the plasma layer, the surface of the uterus shows bluish-purple bruises, which are most obvious at the place where the placenta is attached, and this is called uteroplacental stroke. 2. Systemic changes: A large amount of tissue thromboplastin is released from the placental villi and meconium at the stripped area into the maternal blood circulation, activating the coagulation system and affecting the blood supply, leading to multi-organ dysfunction. At the same time, as the procoagulant substances continue to enter the blood, activating the fibrinolytic system, a large number of coagulation factors are consumed, ultimately leading to coagulation dysfunction. Pregnant women with placenta previa should seek timely medical treatment to minimize the occurrence of adverse pregnancy outcomes.