Placental Abruption

Aka: Placental Abruption, Abruptio Placenta

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II. Definition

  1. Premature placenta separation from uterine wall after 20 weeks gestation
    1. Contrast with Subchorionic Hemorrhage which complicates the first trimester
  2. Accompanied by uterine Hemorrhage

III. Epidemiology

  1. Most common cause of serious bleeding in pregnancy
  2. Most common cause of maternal death due to bleeding
  3. Accounts for 30% of Late Pregnancy Bleeding (in the second half of pregnancy)
  4. Incidence Placental Abruption
    1. All Placental Abruptions: 1-2%
    2. Severe Placental Abruption (Grade 3): 0.2%
  5. Incidence with Trauma
    1. Minor Trauma: 1 to 5%
    2. Major Trauma: 20 to 50%
  6. Risk of recurrence in future pregnancy
    1. One prior Placental Abruption: 5-16%
    2. Two or more prior Placental Abruptions: 25%

IV. Pathophysiology

  1. Maternal vessels rupture in the Decidua basalis where they meet the placental villi (which anchor placenta to Uterus)
  2. Blood collects between the placenta and the Uterus
  3. Results in placental separation and ultimately uteroplacental insufficiency

V. Types: Separation

  1. Marginal sinus separation or marginal sinus rupture
    1. Presumed separation resolves without other findings
  2. Concealed Hemorrhage
  3. Partial abruption
  4. Complete abruption (concealed Hemorrhage)

VI. Risk Factors

  1. Maternal Hypertension
    1. Pregnancy Induced Hypertension or Preeclampsia (most common)
    2. Pre-existing Hypertension
  2. High Parity
  3. Abdominal Trauma
    1. Accounts for a relatively small percentage of the overall number of abruptions
    2. MVA (unrestrained, rapid deceleration)
  4. Previous Placental Abruption (10 fold increased risk)
  5. Twin Gestation (over distention of Uterus)
    1. Related to rapid decompression of distended Uterus
    2. Occurs after delivery of first twin
  6. Polyhydramnios
  7. Maternal Substance Abuse
    1. Cocaine Abuse
    2. Methamphetamine Abuse
  8. Maternal Tobacco Abuse (2 fold increased risk)
  9. Increased msAFP
  10. Maternal Thrombophilia
  11. Advanced maternal age

VII. History

  1. Trauma (MVA, physical abuse)
    1. Usually all or nothing event
    2. Traumatic abruption will occur definitively
    3. Contrast with chronic course for other causes
  2. Pain between contractions
  3. Rupture of Membranes
  4. Abruption risk factors as above

VIII. Symptoms

  1. Vaginal Bleeding (78%)
    1. See Late Pregnancy Bleeding
    2. Quantitate amount of bleeding
    3. Assess color of blood
    4. Bleeding is occult (concealed, occult, hidden behind placenta) in 20% of cases
    5. Consider Vasa Previa if bleeding occurs with SROM
  2. Abdominal Pain (66%)
    1. May be severe and constant
    2. Posterior placenta may present with Low Back Pain
    3. May occur as back-to-back contractions

IX. Signs

  1. Vital Signs suggestive of cardiovascular compromise
    1. Tachycardia
    2. Orthostatic changes in Blood Pressure and pulse
  2. Evaluate for external signs of Trauma
  3. Avoid bimanual exam
    1. Placenta Previa may be indistinguishable initially from Placental Abruption
  4. Fetal evaluation
    1. Fetal Distress (Non-reassuring Fetal Heart Tracing)
      1. Continuous Fetal Heart Tracing
      2. Consider ceserean for persistent Fetal Distress
    2. Fundal height
    3. Fetal Lie
    4. Tocometry monitoring
      1. High resting tone
      2. Small, frequent superimposed contractions
        1. Uterine irritability onset within 4 hours of Trauma (within 2 hours in most cases)
      3. Continue monitoring for minimum of 4 hours following Trauma (ACOG guidelines)
        1. Extend monitoring to 24 hours if criteria met (see below)
  5. Uterus hypertonic or tense (Couvelaire Uterus)
    1. Fundus tender to palpation
    2. Related to concealed clot, bleeding into myometrium

X. Differential Diagnosis

  1. Abdominal Pain
    1. Acute polyhydramnios
    2. Uterine Fibroid degeneration
    3. Uterine Rupture
    4. Chorioamnionitis
    5. Preterm Labor
    6. Peritonitis
      1. Ruptured Peptic Ulcer
      2. Appendicitis
  2. Vaginal Bleeding
    1. See Late Pregnancy Bleeding
    2. Placenta Previa
    3. Vasa Previa
    4. Subchorionic Hemorrhage

XI. Grading: Sher Severity Grading system

  1. Grade 1: (Herald bleed)
    1. Less than 100cc of uterine bleeding
    2. Uterus non-tender
    3. No Fetal Distress
  2. Grade 2
    1. Uterus tender
    2. Fetal Distress
    3. Concealed Hemorrhage
    4. Progresses to Grade 3 without delivery
  3. Grade 3
    1. Fetal death
    2. Maternal shock
    3. Extensive concealed Hemorrhage
    4. Coagulopathy
      1. Absent: 3A (66% of patients)
      2. Present: 3B (33% of patients)

XII. Imaging: Pelvic Ultrasound immediately

  1. Ultrasound Test Sensitivity is only 50% for Placental Abruption
  2. Placental Abruption is a clinical diagnosis
    1. Do not delay definitive management for Ultrasound
    2. Ultrasound should be done if no delay
  3. Ultrasound
    1. Inconsistent findings
      1. Both both clots and placenta are hyperechoic
      2. Differentiating the two is difficult
    2. Findings suggestive of Placental Abruption
      1. Sonolucent area between placenta and Uterus
      2. Rounding of placental edge
      3. Placenta appears thick (variably present)
  4. References
    1. Glantz (2002) J Ultrasound Med 21:837-40 [PubMed]

XIII. Imaging: Major Abdominal Trauma

  1. See Trauma in Pregnancy
  2. CT Abdomen and Pelvis With Contrast
    1. Indications
      1. Stable pregnant patients with significant Blunt Abdominal Trauma
      2. CT Is under-performed in high mechanism injuries
        1. Avoiding indicated CT risks missing serious or life threatening maternal injury
      3. Fetal radiation dose: 25 mGy
        1. Radiation exposure <50 mGy are not associated with fetal loss or anomaly
    2. CT Test Sensitivity up to100% (80% Specificity) when radiologists are cued to look for abruption
      1. Contrast with Ultrasound Test Sensitivity 24-50% (but high Test Specificity 92-96%)
    3. Highly Specific Findings suggestive of Placental Abruption
      1. Hypoenhancement approaching 50% of placental cross-sectional area
      2. Full thickness areas of hypoenhancement
      3. Hypoenhancing Hematoma that undermines placenta with a beaked or acute angle at leading edge
    4. False Positive CT occur in up to 20% of patients (esp. second and third trimester pregnancy)
      1. Heterogeneous contrast enhancement
      2. Small incidental Subchorionic Hemorrhages unrelated to Trauma
      3. Placental cotyledons ectopic from main placenta
      4. Normal low attenuating findings (e.g. chorionic plate indentations, venous lake)
      5. Small wedge placental infarcts may be normal in late pregnancy
    5. References
      1. Broder (2022) Crit Dec Emerg Med 36(10): 18-9
      2. Wei (2009) Emerg Radiol 16(5): 365-73 [PubMed]

XIV. Labs: Initial

  1. Complete Blood Count with Platelets
  2. Blood Type
  3. Kleihauer-Betke
  4. Urinalysis for Urine Protein
  5. Serum Creatinine
  6. Fibrinogen <150 mg/dl suggests Coagulopathy
  7. Also consider
    1. Factor V Leiden
    2. Prothrombin gene mutation
    3. Urine Drug Screen

XV. Labs: Other

  1. Initial labs as above
  2. Thrombomodulin
    1. New marker for Placental Abruption
  3. Coagulation studies
    1. ProTime (PT)
    2. Partial Thromboplastin Time (PTT)
    3. Fibrin split products (Fibrin Degradation Products)
    4. Fibrinogen as above
    5. Clot Test (4-8 minutes is normal clotting time)
      1. Coagulopathy if tube does not clot in 8 minutes
  4. Blood Type and Cross for 4 units
  5. Kleihauer-Betke Test (if Maternal blood Rh Negative)
    1. Indicated if positive sheep rosette test
    2. Not used to diagnose Placental Abruption
    3. Determines RhoGAM dose

XVI. Management: Stable patient (Grade I)

  1. General
    1. Obstetrics Consultation
    2. RhoGAM if Maternal blood Rh Negative
  2. Criteria
    1. Reassuring Fetal Heart Tracing
    2. No Coagulopathy
    3. Normotensive without Preeclampsia
    4. Nontender Uterus
    5. Negative Ultrasound with normal AFI
  3. Preterm gestation
    1. Consider Tocolysis with Magnesium Sulfate
      1. Contraindicated in all but mild abruption <34 weeks
      2. Controversial and risky
    2. Steroids to promote lung maturity
    3. Consider Amniocentesis for lung maturity studies
    4. External Fetal Monitoring
    5. Observe during short term hospitalization
      1. Minimum of 4 hour observation on tocometry after Trauma
      2. Criteria to extend to at least 24 hour observation after Trauma
        1. Contractions >4-6/hour
        2. Abdominal or uterine tenderness
        3. Significant other injuries
        4. Vaginal Bleeding
        5. Ruptured membranes
        6. Fetal Distress
  4. Term gestation or mature lung studies
    1. Active management labor towards rapid fetal delivery
    2. Early Rupture of Membranes (AROM)
    3. Internal Fetal Monitoring (fetal scalp electrode)
    4. Tocometry
    5. Intrauterine Pressure Catheter
    6. Cautious use of Pitocin
  5. Risks
    1. Preterm birth
    2. Intrauterine Growth Retardation

XVII. Management: Emergent

  1. Precautions
    1. Rapid management is critical
    2. Fetal death occurs in up to 30% within 2 hours
    3. Do not delay management for Ultrasound confirmation
      1. Ultrasound is unreliable for diagnosis
      2. Placental Abruption is a clinical diagnosis
  2. Indications
    1. Brisk bleeding
    2. Unstable Vital Signs
    3. Fetal Distress
    4. Grade II or III Placental Abruption
  3. Immediate interventions
    1. Oxygen
    2. Trendelenburg position
    3. Obtain immediate Intravenous Access and manage Hemorrhagic Shock
      1. Two large bore IV (16-18 gauge)
      2. Initiate Isotonic crystalloid bolus
        1. Normal Saline
        2. Lactated Ringers
      3. Packed Red Blood Cell Transfusion
    4. Call for immediate Obstetric and neonatal support
    5. Delivery within 20 minutes if Fetal Distress
      1. Cesarean Section unless imminent Vaginal Delivery
    6. RhoGAM if Maternal blood Rh Negative
  4. Monitoring
    1. Orthostatic Blood Pressure and pulse
    2. Monitor Intake and output
      1. Keep Urine Output over 30cc per hour
    3. Monitor Hemoglobin or Hematocrit q1-2 hours prn
      1. Keep Hemoglobin >10 g/dl or Hematocrit >30%
      2. Packed Red Blood Cell Transfusion as needed
    4. Monitor coagulation studies (see labs above)
      1. Fresh Frozen Plasma transfusion as needed
      2. Platelet Transfusion as needed

XVIII. Complications

  1. Maternal complications
    1. Prolonged Hypovolemic Shock
    2. Renal Cortical necrosis
    3. Coagulopathy
      1. Consumptive Coagulopathy
      2. Disseminated Intravascular Coagulation (DIC)
        1. Results from thromboplastin release
    4. Amniotic Fluid Embolism
    5. Maternal Death
    6. Uteroplacental apoplexy (Couvelaire Uterus)
      1. Bleeding into myometrium results in hypotonic wall
      2. Risk of Postpartum Hemorrhage
  2. Fetal complications
    1. Intrauterine Growth Retardation
    2. Preterm Labor
    3. Intrauterine Fetal Demise
      1. Risk is related to degrees of separation
      2. Fetal death in up to 30% of cases

XIX. References

  1. Bavolek (2018) EM:Rap 18(12):4-5
  2. Krywko and Jennings (2018) Crit Dec Emerg Med 32(4): 3-11
  3. Lall (2017) Crit Dec Emerg Med 31(1): 3-9
  4. Ananth (1999) JAMA 282:1646-51 [PubMed]
  5. Sakornbut (2007) Am Fam Physician 75:1199-206 [PubMed]

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