Placental abruption - NYSORA

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Placental abruption

Learning objectives

  • Signs of placental abruption 
  • Degrees of placental abruption 
  • Management of placental abruption 

Definition and mechanisms

  • Hemorrhage arising from the premature separation of a normally situated placenta 
  • Separation of the placental bed from the decidua basalis before delivery of the fetus
  • Occurs in 1% of pregnancies 
  • Leading cause of vaginal bleeding in the latter half of pregnancy
  • Emergency with high maternal and fetal morbidity/mortality
  • Major complications: 

Signs and symptoms 

  • Key diagnostic factors: 
    • Vaginal bleeding (although about 20% of cases have no bleeding) 
    • Uterine tenderness 
    • Rapid contractions 
    • Abdominal pain 
    • Fetal heart rate abnormalities 
  • The clinical implications of a placental abruption vary based on the extent of the separation and the location of the separation
  • Placental abruption can be complete or partial and marginal or central
  • The classification of placental abruption is based on the following clinical findings: 

Class 0: asymptomatic
Class 1: mildClass 2: moderate Class 3: Severe
Discovery of a blood clot on the maternal side of a delivered placenta
Diagnosis is made retrospectively
No sign of vaginal bleeding or a small amount of vaginal bleeding
Slight uterine tenderness
Maternal blood pressure and heart rate within normal limits
No signs of fetal distress
No sign of vaginal bleeding to a moderate amount of vaginal bleeding
Significant uterine tenderness with tetanic contractions
Change in vital signs: maternal tachycardia, orthostatic changes in blood pressure
Evidence of fetal distress
Clotting profile alteration: hypofibrinogenemia
No sign of vaginal bleeding to heavy vaginal bleeding
Tetanic uterus/board-like consistency on palpation
Maternal shock
Clotting profile alteration: hypofibrinogenemia and coagulopathy
Fetal death

  • Classification of 0 or 1 is usually associated with a partial, marginal separation
  • Whereas, classification of 2 or 3 is associated with complete or central separation

Stages of hypovolemic shock

I CompensatedII MildIII ModerateIV Severe
Blood loss <15%; 750–1000 ml 15–30%; 1000–1500 ml 30–40%; 1500–2000 ml>40%; ≥2000 ml
Heart rate (beats/min) <100 >100 >120 >140
Arterial pressureNormal; vasoconstriction redistributes blood flow, slight increase in diastolic pressure Orthostatic changes in arterial pressure, vasoconstriction intensifies in non-critical organs (skin, muscle, gut) Markedly decreased (systolic arterial pressure <90 mm Hg); vasoconstriction decreases perfusion to abdominal organs Profoundly decreased (systolic arterial pressure <80 mm Hg); decreased perfusion to vital organs (brain, heart)
RespirationNormal Mild increase Moderate tachypnea Marked tachypnea—respiratory failure
Mental statusNormal, slightly anxious Mildly anxious, agitated Confused, agitated Obtunded
Urine output (ml/h)>3020-30<20None (anuria)
Capillary refillNormal (<2 s)>2 s; clammy skin Usually >3 s; cool, pale skin >3 s; cold, mottled skin

Risk factors 


  • The exact etiology is unknown 
  • Specific cause is often unknown 
  • Trauma or injury to the abdomen 
  • Rarely a short umbilical cord or rapid loss of amniotic fluid 


  • Clinical signs/symptoms 
  • Ultrasound (however low sensitivity)


Placental abruption, advanced life supprt, fetus, cesarean birth, hypertonic contrations

Suggested reading 

  • Schmidt P, Skelly CL, Raines DA. Placental Abruption. In: StatPearls. Treasure Island (FL): StatPearls Publishing; April 1, 2022.
  • Walfish, M., Neuman, A., Wlody, D., 2009. Maternal haemorrhage. British Journal of Anaesthesia 103, i47–i56.

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