Postpartum Hemorrhage

Postpartum hemorrhage (PPH) poses a significant risk to maternal health and is characterized by excessive blood loss after delivery. While uterine contractions and the coagulation cascade primarily regulate blood loss, PPH can lead to severe complications if untreated. Based on blood loss thresholds, the traditional definition of PPH has evolved to encompass broader criteria reflecting signs of hypovolemia. Traditionally, PPH is defined as more than 500 mL of estimated blood loss in a vaginal delivery or more than 1000 mL of estimated blood loss during Cesarean delivery. These parameters were redefined in 2017 by the American College of Obstetrics and Gynecology as a cumulative blood loss of more than 1000 mL with signs and symptoms of hypovolemia within 24 hours of the birth process, regardless of the mode of delivery. Though this change was made with the knowledge that blood loss at the time of delivery is routinely underestimated, more than 500 mL of blood loss at the time of vaginal delivery should be considered abnormal with the potential need for intervention.

PPH is frequently subdivided based on symptom onset. Primary PPH is hemorrhage that occurs between the third stage of labor (ie, delivery of the placenta) and 24 hours after fetal delivery; secondary PPH occurs more than 24 hours after delivery—up to 12 weeks postpartum. Causes, summarized by the 4 "T's" (tone, trauma, tissue, thrombin), require prompt intervention. Management involves a multidisciplinary approach, emphasizing blood loss assessment, fluid replacement, and source control. Despite advancements, PPH prevention and prediction remain essential to maternal well-being. PPH poses a significant challenge in obstetrics, complicated by difficulties in accurately estimating blood loss, as cognitive biases can lead to delays in diagnosis and management. Though more accurate, quantitative blood loss measurement methods have not consistently improved clinical outcomes. Interprofessional approaches, including PPH bundles and perinatal quality collaboratives, reduce morbidity. Management involves a coordinated effort addressing uterine atony, genital tract lacerations, retained placental tissue, and coagulopathy, with surgical interventions like hysterectomy as a last resort. Prevention strategies include active management of the third stage of labor and prenatal identification of high-risk factors. Vigilance and prompt intervention remain crucial in mitigating maternal morbidity and mortality associated with PPH.