Placental abruption of one quarter of the area, close to 30%, predisposes to coagulation disorders and is often more severe, and the severity of the condition is related to its grading. Placental abruption is the detachment of the placenta from its normal uterine position before delivery of the fetus after 20 weeks and is a serious complication in late pregnancy. Its severity is related to its grading, with grade 0 and I having less severe symptoms, and grade II and III having more severe symptoms. Placental abruption is often more than 50% of the total area of the placenta in pregnant women with intrauterine fetal death, and coagulation disorders are often seen in close to 30% of the total area of the placenta. Placental abruption is a serious complication in late pregnancy, and often develops rapidly, which can endanger the life of the mother and child in severe cases, and is often associated with hypertension in pregnancy, chronic hypertension, premature rupture of membranes in early pregnancy, etc. When vaginal bleeding, abdominal pain and other discomforts occur in the late pregnancy, the hospital should be timely to avoid an adverse outcome.