Abruptio Placentae

Snapshot

• A 30-year-old G1P0 woman at 36 weeks of gestation presents to the emergency room with sudden onset of moderate back pain and strong uterine cramping that began 2 hours ago. Thirty minutes prior to the onset of back pain, she noted bright red vaginal bleeding. She has had no prenatal care. On physical exam she is afebrile; her blood pressure is 130/80 mmHg, pulse is 109/min, and respirations are 18/min. Abdominal palpation reveals a gravid, hypertonic uterus and palpable uterine contractions. You observe blood in the vaginal vault. Results of transabdominal ultrasound demonstrate retroplacental hemorrhage.

Introduction

• Overview 
  • partial or complete placental detachment prior to delivery of the fetus
  • diagnosis typically only applies to pregnancies > 20 weeks of gestation
    • placenta abruptio and placenta previa are the 2 most common causes of third trimester bleeding
• Epidemiology
  • incidence
    • ~1% of all pregnancies
      • 2/3 of cases are “severe” based on maternal, fetal, and neonatal morbidity
  • demographics
    • more common in African-American women
  • risk factors  
    • prior placental abruption
    • trauma (e.g., motor vehicle accident)
    • maternal smoking
    • cocaine use
    • hypertensive disorders
      • eclampsia
      • preeclampsia
      • chronic hypertension
    • premature rupture of membranes
    • uterine structural abnormalities
      • bicornate uterus
      • uterine synechiae
      • leiomyoma
    • abnormalities of maternal serum biochemical markers
      • increased alpha fetoprotein
      • increased hCG
      • very low or very high levels of inhibin A
    • hyperhomocystinemia
• Pathophysiology
  • rupture of maternal vessels in the decidua basalis
    • bleeding into the decidual-placental interface causes placental separation from the uterine wall
• Prognosis
  • mother
    • increased morbidity and mortality
      • prompt intervention decreases the incidence of maternal mortality
    • increased long-term risk of premature cardiovascular disease
    • 2x risk of death after coronary artery revascularization in the future
      • may reflect underlying maternal vascular abnormalities that manifest as abruption during pregnancy
  • fetus
    • increased morbidity and mortality
• especially when preterm

Presentation

• Symptoms
  • abrupt third trimester bleeding 
  • abdominal and/or back pain 
  • uterine contractions
• Physical exam
  • vital signs consistent with bleeding if severe
    • hypotension
    • tachycardia
  • gravid hypertonic uterus
  • uterine tenderness
  • blood/clots may be observed in the vaginal vault
  • fetal distress
• nonreassuring fetal heart rate pattern

Imaging

• Ultrasound 
  • indications
    • diagnosis of retroplacental hematoma
      • classic for placental abruption
      • usually present if abruption is more severe
      • may be absent in milder cases of abruption
• used to rule out placenta previa

Studies

• Serum fibrinogen
  • has the best correlation with severity of bleeding, presence of DIC, and need for blood products
  • ≤ 200 mg/dL predicts severe postpartum hemorrhage
• Pathologic placental evaluation
• supports the clinical diagnosis

Differential

• Placenta previa 
  • key distinguishing feature
    • presents as painless vaginal bleeding
• Uterine rupture 
  • also associated with trauma
  • may also have sudden onset symptoms
    • vaginal bleeding
    • abdominal pain
    • fetal heart rate abnormalities
    • maternal hypotension and tachycardia
  • key distinguishing features
    • loss of uterine tone/contractions
    • occurs after onset of labor
    • other risk factors
      • previous C-section
• Normal or pre-term labor
  • key distinguishing feature
• has more gradual onset of signs/symptoms

Treatment

• Medical
  • expectant management with continuous fetal monitoring
    • indications
      • when both the mother and fetus are stable and the fetus is < 34 weeks gestation
  • fluid replacement
    • indications
      • all patients with signs of bleeding
    • modalities
      • placement of 1-2 large-bore intravenous lines
      • administer lactated ringers (LR) to maintain urine output > 30 mL/hr
  • serum studies
    • indications
      • all patients with suspected plantental abruption
    • modalities
      • complete blood count (CBC)
      • blood type and screen
        • with crossmatch if transfusion is likely
      • coagulation studies
      • liver chemistries
        • in patients with suspected preeclampsia or HELLP syndrome
  • RhoGAM 
    • indications 
      • all Rh(D)-negative mothers with vaginal bleeding if father is Rh(D)-positive or unknown 
    • modalities 
      • single intramuscular or intravenous dose 
  • vaginal delivery
    • indications
      • fetus is ≥ 36 weeks gestation
      • no other indications for cesarean delivery
    • if the patient is not in active labor
      • amniotomy and oxytocin administration
    • administer standard delivery medications
      • group B streptococcus prophylaxis according to guidelines
      • magnesium sulfate for neuroprotection if < 32 weeks of gestation
• Surgical
  • immediate delivery with cesarean delivery
    • indications
      • non-reassuring fetal status 
      • hemodynamic instability in the mother
      • if fetus is 34-36 weeks gestation
• due to risk of progressive placental separation and maternal/fetal compromise

Complications

• Disseminated intravascular coagulation (DIC)
  • when placental separation > 50%
• Hemorrhagic shock
• Maternal death
• Recurrence risk in future pregnancies
  • 3-15% have a recurrence
• Fetal anemia
• Fetal death
  • when placental separation >50%