After 20 weeks of gestation or during labor, the placenta in its normal position is partially or completely detached from the uterine wall before the delivery of the fetus, which is called placental abruption. Placental abruption is a serious complication in late pregnancy, with rapid onset and progression, which can endanger the life of mother and child if not treated in time. The incidence of placental abruption is 4,6‰ to 21‰ in China and 5,1‰ to 23,3‰ in foreign countries. The incidence is related to whether the placenta is carefully examined after delivery. Some mild placental abruptions may have no obvious symptoms before delivery, and only during postpartum examination of the placenta, clot pressure is found at the abruptio, which is easily ignored in such patients. The abdominal examination shows that the uterus is hard like a plate on palpation and there is pressure pain, especially at the placenta attachment area. The pathogenesis of placental abruption has not been completely elucidated, and its development may be related to the following factors. 1, vascular lesions Pregnant women with placenta abruptio are complicated by severe hyperemesis, chronic hypertension and chronic kidney disease, especially those with systemic vascular lesions. When the spiral small arteries of the bottom metaphorical membrane spasm or sclerosis, causing ischemic necrosis of the distal capillaries, resulting in rupture and bleeding, blood flows to the bottom metaphorical layer to form a hematoma, resulting in placenta abruption from the uterine wall. 2, mechanical factors Trauma (especially direct impact on the abdomen or falling abdomen in direct contact with the ground, etc.), external inversion surgery to correct fetal position, short umbilical cord or umbilical cord around the neck, and falling of the fetal first dewlap during labor, may all contribute to placental abruption. In addition, in twin pregnancies, the first fetus is delivered too quickly or the amniotic fluid flows out too quickly when the membranes are broken, causing a sudden decrease in intrauterine pressure and sudden contraction of the uterus, which may also lead to placental abruption from the uterine wall. 3, sudden increase in uterine venous pressure Late pregnancy or after delivery, when the mother takes the supine position for a long time, supine hypotension syndrome can occur. At this time, due to the huge pregnant uterus compressing the inferior vena cava, the amount of cardiac blood return decreases and the blood pressure drops, while the uterine veins are stagnant and the venous pressure rises, leading to stasis or rupture of the meconium vein bed, resulting in partial or total placental abruption from the uterine wall.