There are several methods to assess the approximate amount of bleeding when postpartum hemorrhage occurs. Normally, a curved dish can be placed at the vaginal opening after childbirth. By collecting blood in this curved dish, you can understand the specific amount of bleeding. Alternatively, the gauze method can be used, estimating the amount of bleeding based on the specific area of each piece of gauze. Another method involves monitoring changes in the patient's vital signs and using the specific timing of shock indices to determine the amount of bleeding. However, it is crucial to promptly implement hemostasis to avoid severe consequences.