Placental abruption

Learning objectives

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:
- Hemorrhagic shock
- Acute kidney injury
- Coagulopathy
- Fetal demise
- Maternal death
- Delivering premature infant
- Transfusion-associated complications
- Hysterectomy
- Recurrence has been reported in 4 to 12% of cases

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: mild	Class 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 Compensated	II Mild	III Moderate	IV 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 pressure	Normal; 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)
Respiration	Normal	Mild increase	Moderate tachypnea	Marked tachypnea—respiratory failure
Mental status	Normal, slightly anxious	Mildly anxious, agitated	Confused, agitated	Obtunded
Urine output (ml/h)	>30	20-30	<20	None (anuria)
Capillary refill	Normal (<2 s)	>2 s; clammy skin	Usually >3 s; cool, pale skin	>3 s; cold, mottled skin