Definition/General
Introduction:
Placental abruption (abruptio placentae) is the premature separation of a normally implanted placenta from the uterine wall before delivery of the fetus
It occurs in 0.4-1.5% of all pregnancies
It is a major cause of maternal and perinatal morbidity and mortality
The condition leads to retroplacental hemorrhage and subsequent complications.
Origin:
Results from rupture of maternal vessels in the decidua basalis
The bleeding occurs between the placental surface and the uterine wall
This leads to retroplacental hematoma formation
The hematoma compresses placental tissue
It compromises maternal-fetal circulation
Progressive separation may occur if bleeding continues.
Classification:
Classified by severity: Grade I (mild)
Grade II (moderate)
Grade III (severe)
By location: Marginal (external bleeding)
Concealed (internal bleeding)
Mixed type (partial external bleeding)
By extent: Partial separation
Complete separation.
Epidemiology:
Incidence: 0.4-1.5% of pregnancies
Maternal mortality: 1-5%
Perinatal mortality: 15-25%
Risk increases with advanced maternal age
Higher incidence in multiparity
Recurrence risk: 5-17% in subsequent pregnancies
More common in third trimester.
Clinical Features
Presentation:
Vaginal bleeding (80% cases)
Abdominal pain (70% cases)
Uterine tenderness and rigidity
Fetal distress or demise
Maternal shock (severe cases)
Coagulopathy (DIC)
Premature labor.
Symptoms:
Sudden onset severe abdominal pain
Dark red vaginal bleeding
Back pain
Nausea and vomiting
Decreased fetal movements
Maternal weakness
Syncope (severe bleeding).
Risk Factors:
Hypertensive disorders (preeclampsia, chronic hypertension)
Previous abruption (major risk factor)
Trauma (motor vehicle accidents, domestic violence)
Smoking and cocaine use
Advanced maternal age (>35 years)
Multiparity
Polyhydramnios
Multiple gestation
Thrombophilia.
Screening:
Ultrasound examination (limited sensitivity)
Clinical assessment (primary diagnostic tool)
Fetal monitoring
Laboratory tests (CBC, coagulation studies)
Kleihauer-Betke test (fetomaternal hemorrhage).
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Gross Description
Appearance:
Retroplacental hematoma on maternal surface
Dark, clotted blood adherent to decidua
Indentation on placental surface corresponding to hematoma
Pale, compressed areas of placental tissue
Marginal bleeding in external abruption.
Characteristics:
Organized clot firmly adherent to maternal surface
Central depression on placental parenchyma
Fibrin deposition in compressed areas
Areas of infarction
Intervillous fibrin deposition.
Size Location:
Hematoma size varies from small (<5 cm) to large (>10 cm)
Most commonly occurs at placental periphery
Central abruption more severe
Complete separation involves entire placental surface
Partial separation affects <20% of surface.
Multifocality:
Multiple small hematomas may be present
Coalescent pattern in severe cases
Marginal extension from central focus
Bilateral involvement possible in complete separation.
Microscopic Description
Histological Features:
Acute hemorrhage in decidua basalis
Villous compression and collapse
Intervillous fibrin deposition
Decidual necrosis
Inflammatory infiltrate
Thrombosis of spiral arteries.
Cellular Characteristics:
Extravasated red blood cells in decidua
Collapsed chorionic villi
Syncytial knots increased
Trophoblast ischemia
Decidual cell necrosis
Neutrophilic infiltration.
Architectural Patterns:
Compressed villous architecture
Intervillous space filled with fibrin and blood
Decidual separation planes
Vascular thrombosis
Ischemic villous changes.
Grading Criteria:
Grade I: <20% placental surface
Minimal maternal symptoms
Grade II: 20-50% separation
Moderate bleeding
Grade III: >50% separation
Severe maternal and fetal compromise
Couvelaire uterus may be present.
Immunohistochemistry
Positive Markers:
CD68 (macrophages in hematoma)
Factor VIII (endothelial cells)
Smooth muscle actin (vascular smooth muscle)
CD34 (endothelial marker)
Fibrinogen (fibrin deposition).
Negative Markers:
Cytokeratin (in necrotic areas)
Desmin (muscle necrosis)
Special stains not routinely required for diagnosis
Clinical correlation is primary.
Diagnostic Utility:
Limited role in routine diagnosis
Research applications for studying pathogenesis
CD68 helpful in chronic cases
Vascular markers assess vessel integrity.
Molecular Subtypes:
Acute abruption (fresh hemorrhage)
Chronic abruption (organized hematoma)
Recurrent abruption (multiple episodes)
Associated with maternal vascular disease.
Molecular/Genetic
Genetic Mutations:
Thrombophilia genes (Factor V Leiden, Prothrombin G20210A)
MTHFR mutations
Protein C deficiency
Protein S deficiency
Antithrombin deficiency.
Molecular Markers:
D-dimer elevation
Fibrin degradation products
Decreased fibrinogen
Platelet consumption
Activated partial thromboplastin time prolongation.
Prognostic Significance:
Thrombophilia increases recurrence risk
Severe coagulopathy indicates poor prognosis
Extent of separation correlates with outcomes
Fetal compromise determines neonatal prognosis.
Therapeutic Targets:
Anticoagulation in thrombophilia
Antihypertensive therapy
Smoking cessation
Low-dose aspirin in high-risk patients
Folic acid supplementation.
Differential Diagnosis
Similar Entities:
Placenta previa (bleeding without pain)
Vasa previa (fetal vessel rupture)
Uterine rupture (different pain pattern)
Marginal sinus rupture (minimal clinical significance)
Cervical/vaginal bleeding.
Distinguishing Features:
Abruption: Painful bleeding
Uterine tenderness
Fetal distress
Previa: Painless bleeding
Soft uterus
Abnormal placental location
Vasa previa: Fetal bradycardia
Kleihauer-Betke negative.
Diagnostic Challenges:
Concealed abruption may lack bleeding
Mild cases difficult to diagnose
Ultrasound limitations
Chronic abruption vs oligohydramnios
Multiple pregnancy complications.
Rare Variants:
Chronic abruption (oligohydramnios sequence)
Total abruption with fetal death
Marginal abruption (bleeding only)
Couvelaire uterus (uterine apoplexy).
Sample Pathology Report
Template Format
Sample Pathology Report
Complete Report: This is an example of how the final pathology report should be structured for this condition.
Specimen Information
Placenta with membranes and umbilical cord, weighing [X] grams
Diagnosis
Placental abruption with retroplacental hematoma
Classification
Grade [I/II/III] abruption involving [X]% of placental surface
Gross Findings
Retroplacental hematoma measuring [X] cm, adherent clot, placental indentation
Microscopic Findings
Acute hemorrhage in decidua basalis, villous compression, intervillous fibrin
Extent of Abruption
Affects approximately [X]% of placental surface area
Associated Findings
Infarction: [present/absent], Chorioamnionitis: [present/absent]
Clinical Correlation
Findings consistent with clinical presentation of [severity] abruption
Recommendations
Correlation with maternal coagulation studies and neonatal outcomes
Final Diagnosis
Placental abruption, Grade [I/II/III]