The causes of postpartum hemorrhage can be broadly summarized into four main factors: 1) Inadequate uterine contraction. 2) Lacerations in the soft birth canal. 3) Placental factors. 4) Coagulation dysfunction. The most common cause in clinical settings is inadequate uterine contraction. The manifestation of inadequate uterine contraction primarily appears as the placenta and membranes being expelled intact postpartum, no injuries in the soft birth canal, and an unclear uterine contour upon palpation. The uterus becomes firm when massaged and softens when the massage stops. This condition is indicative of postpartum hemorrhage caused by inadequate uterine contraction. Postpartum hemorrhage due to lacerations in the soft birth canal typically presents as immediate bleeding following the delivery of the baby. The blood is bright red and may contain clots, which mostly suggests lacerations in the soft birth canal. If significant bleeding occurs about five to ten minutes after the delivery of the placenta and baby, this is generally considered to be related to placental factors. If the bleeding is unclotted and continuous, this severe hemorrhage might be due to a coagulation dysfunction.