Postpartum hemorrhage complicates approximately 5 % of all deliveries. It is the second leading cause of maternal mortality, causing approximately one-sixth of all such deaths. All deliveries are associated with blood loss. Postpartum hemorrhage is defined as blood loss in excess of 500 cc. Actual blood loss during the course of routine delivery may exceed 500 cc if carefully measured. Although the definition of postpartum hemorrhage remains unchanged, from a practical standpoint, postpartum hemorrhage is often understood as hemorrhage that persists beyond expectation. Early postpartum hemorrhage is defined as blood loss occurring in the first 24 h postpartum. Late postpartum hemorrhage is defined as blood loss occurring between 24 h and 12 weeks’ postpartum.

Following delivery of the infant, normal bleeding is controlled by separation of the placenta, uterine contraction with constriction of placental bed vessels and normal hemostatic pathways. Postpartum hemorrhage occurs when one or more of these events are disrupted. Postpartum hemorrhage may be caused by a variety of obstetrical complications including uterine atony, lacerations, retained placenta, and obstetrically related coagulopathy. Most cases of postpartum hemorrhage are caused by obstetrical complications; however, providers should also be aware that pre-existing coagulopathies may also manifest as postpartum hemorrhage.