Postpartum hemorrhage usually occurs within 24 hours after delivery, and is more common within 2 hours after delivery. Postpartum hemorrhage is defined as bleeding more than 500ml within 24 hours after delivery, and more than 1000ml for cesarean delivery. there are many reasons for postpartum hemorrhage, mainly including weak contraction of uterus after delivery, poor suturing in cesarean delivery, residual placenta and fetal membranes, coagulation dysfunction, soft birth canal injury and tear, etc. These factors will cause postpartum hemorrhage in a relatively short period of time. In particular, postpartum hemorrhage caused by weak uterine contractions often occurs within 2 hours after delivery of the placenta. A woman who has postpartum hemorrhage will lose a lot of blood in a short period of time, which can easily cause shock and even endanger her life. Therefore, immediate resuscitation is required, including surgery to stop bleeding if necessary, and even blood transfusion therapy.