What is the definition of postpartum hemorrhage (PPH), its types (primary, reactionary, and secondary), and associated complications?

Definition and Classification of Postpartum Hemorrhage

Definition

Postpartum hemorrhage (PPH) is defined as any hemorrhage associated with signs or symptoms of hypovolemia within 24 hours of delivery, regardless of the type of delivery, or quantitatively as blood loss ≥500 mL after vaginal delivery or ≥1000 mL following cesarean section. 1, 2

Types of PPH

Primary (Early) PPH

• Occurs within the first 24 hours after delivery 1, 2
• Represents the most common and life-threatening form of postpartum hemorrhage 1
• Affects 1% to 5% of all deliveries 1

Secondary (Late/Delayed) PPH

• Occurs from 24 hours up to 6 weeks (or 12 weeks by some definitions) postpartum 1, 2
• Less common than primary PPH but still clinically significant 1

Reactionary PPH

• The term "reactionary" is not consistently used in current international guidelines 1
• Historically, this term has been used interchangeably with early secondary PPH (occurring within the first few days after the initial 24-hour period), but modern classification systems primarily use the binary distinction of primary versus secondary 1, 2

Causes by Type

Primary PPH Causes

Uterine atony is the most common cause, responsible for more than 75% of all primary PPH cases 3

Additional causes include:

• Trauma (lacerations, uterine rupture, hematomas) - the second most common category 3
• Retained products of conception (RPOC) with or without superimposed infection 1, 3
• Coagulopathy including DIC, amniotic fluid embolism, placental abruption, severe pre-eclampsia, or HELLP syndrome 1, 3
• Placental attachment disorders (adherent placenta, placenta accreta spectrum) 1
• Vascular complications including bladder flap hematoma, subfascial/prevesical hematoma, and perivaginal space hematoma 1
• Uterine rupture or scar dehiscence 1

Secondary PPH Causes

• Uterine atony (can persist or recur) 1
• Vascular uterine anomalies (VUA) representing subinvolution of the placental bed 1
• Retained products of conception - the second most common etiology for PPH overall, typically seen in delayed PPH 1
• Placental attachment disorders 1
• Infection/endometritis 1
• Gestational trophoblastic disease (rare) 1

Complications of PPH

Immediate Life-Threatening Complications

Maternal hypovolemia and hypotension leading to tissue hypoxia, onset of anaerobic metabolism, and multiorgan failure represent the most critical immediate complications 2

• Hemorrhagic shock with potential for cardiac arrest and maternal death 2
• Coagulopathy development: Fibrinogen levels <2 g/L occur in 17% of cases with blood loss exceeding 2000 mL, indicating evolving coagulopathy 3
• Disseminated intravascular coagulation (DIC) complicating the hemorrhage 3

Organ System Complications

• Renal failure secondary to acute tubular necrosis from prolonged hypotension 2
• Hepatic dysfunction from ischemic injury 2
• Acute respiratory distress syndrome (ARDS) 2
• Myocardial ischemia or infarction in severe cases 2
• Cerebral hypoxia with potential for neurological sequelae 2

Surgical and Intervention-Related Complications

• Emergency hysterectomy with loss of fertility - the ultimate life-saving procedure when other measures fail 4
• Complications from massive transfusion including transfusion reactions, citrate toxicity, hypothermia, and transfusion-related acute lung injury 5
• Surgical complications from emergency procedures including infection, poor wound healing (especially in women on long-term corticosteroids), and adhesion formation 1
• Uterine artery or internal iliac artery ligation complications 1
• Embolization-related complications including non-target embolization 1

Long-Term Complications

• Sheehan syndrome (postpartum pituitary necrosis) from severe hemorrhagic shock 2
• Anemia requiring prolonged iron supplementation or blood transfusion 2
• Post-traumatic stress disorder from the traumatic experience 2
• Increased risk of recurrent PPH in subsequent pregnancies (3.5-fold increased risk) 6
• Thromboembolic complications from immobility and coagulopathy, particularly after cesarean section 1

Complications Specific to Treatment Modalities

• Bronchospasm from prostaglandin F2α or ergometrine use, particularly in women with asthma 1
• Respiratory depression from opioid analgesia, especially problematic in women with underlying respiratory disease 1
• Infection risk in women requiring uterine packing or balloon tamponade 1

Critical Pitfalls to Avoid

• Do not wait for laboratory confirmation of DIC before initiating massive transfusion protocol when blood loss exceeds 1,500 mL - immediate blood product administration in fixed ratios is recommended while addressing the underlying cause 3
• Avoid using prostaglandin F2α in women with asthma due to bronchoconstriction risk 1
• Do not delay surgical intervention if medical management fails - early aggressive intervention is critical 7
• Recognize that PPH can occur without identifiable risk factors - maintain vigilance in all deliveries 8