The etiology of placental abruption is due to vascular lesions, mechanical factors, intrauterine pressure sudden decrease and other factors leading to placental and uterine wall detachment. 1. Vascular lesions: pregnant women with hypertensive disorders of pregnancy or pregnancy combined with chronic kidney disease, resulting in spasm or sclerosis of small spiral arteries in the bottom meconium, causing capillary degeneration or necrosis, or even rupture and bleeding, or in the late stages of pregnancy, uterine venous stasis, increased venous pressure, hemorrhage of the bed of the meconium veins, the bottom of the meconium and the uterine wall forming a hematoma between the placenta and the uterine wall, which led to abrupt abruption of the placenta and the uterine wall. 2. Mechanical factors: blunt abdominal trauma leads to sudden uterine contraction, inducing placental abruption. 3. Sudden decrease of pressure in the uterine cavity: twin pregnancies, rapid delivery of the first child, rapid outflow of amniotic fluid after artificial rupture of membranes, etc., resulting in a sudden decrease of pressure in the uterine cavity, sudden uterine contraction, misalignment of the placenta with the wall of the uterus and detachment. In the clinic, if the placenta previa occurs, it is necessary to seek medical treatment in time to avoid delaying the condition.