What is the management of placenta previa?

Management of Placenta Previa

The management of placenta previa requires referral to a level III or IV maternal care center with experience in managing these high-risk cases, with planned cesarean delivery at 34-35 weeks gestation for stable patients with complete placenta previa. 1

Diagnosis and Evaluation

• Initial diagnosis requires both transabdominal and transvaginal ultrasound:
  • Transvaginal ultrasound is safe and preferred for detailed evaluation 1
  • Doppler ultrasound is essential for identifying vascular patterns and distinguishing fetal from maternal vessels 2
  • Follow-up examinations should be scheduled at 28-30 weeks and 32-34 weeks to:
    • Assess potential placenta previa resolution
    • Plan for delivery
    • Evaluate for possible placenta accreta spectrum disorder (PASD) 1

Risk Stratification

• High-risk factors requiring increased surveillance:
  • Prior cesarean delivery (risk increases 7-fold after one cesarean, 56-fold after three) 2
  • Prior uterine surgery or trauma
  • Advanced maternal age
  • In vitro fertilization
  • Multiparity 2

Management Algorithm

Antepartum Management

1. Asymptomatic Patients:

   • Outpatient management with activity modification
   • Pelvic rest (no sexual intercourse)
   • Regular follow-up ultrasounds
   • Patient education on warning signs requiring immediate attention 1

2. Symptomatic Patients (with bleeding):

   • Initial hospitalization for stabilization
   • After stabilization (≥72 hours without bleeding), selected patients may be managed as outpatients 3
   • Outpatient management shows similar outcomes to inpatient management with significant cost savings (average 18.5 fewer hospital days) 3

3. Recurrent Bleeding Episodes:

   • Immediate hospitalization
   • Consider antenatal corticosteroids if <34 weeks
   • Prepare for possible emergency delivery 1

Delivery Planning

1. Timing:

   • 34-35 weeks is optimal for planned cesarean delivery in stable patients 2, 1
   • Earlier delivery may be required for:
     • Persistent bleeding
     • Preeclampsia
     • Labor
     • Rupture of membranes
     • Fetal compromise 2

2. Preoperative Preparation:

   • Multidisciplinary team involvement (maternal-fetal medicine, anesthesiology, neonatology, blood bank)
   • Type and cross-match for at least 4 units of blood
   • Consider cell salvage techniques if anticipated blood loss >1500mL 4
   • Antenatal corticosteroids for lung maturity if delivery before 37 weeks 2

3. Surgical Approach:

   • Cesarean delivery is standard for complete placenta previa 1
   • Consider vaginal delivery only when placental edge is >2cm from internal cervical os 5
   • If placenta accreta is suspected, plan for possible cesarean hysterectomy 2
   • Avoid forced placental removal if accreta is encountered, as this can cause profuse hemorrhage 1

Special Considerations

Placenta Accreta Spectrum

• When placenta previa overlies a previous cesarean scar, evaluate carefully for placenta accreta 2
• Management requires additional planning:
  • Consider preoperative ureteric stent placement if bladder involvement is suspected
  • Prepare for possible cesarean hysterectomy
  • Do not attempt placental removal if accreta is confirmed 2

Travel Restrictions

• Air travel is contraindicated for women with placenta previa, especially after 28 weeks gestation 1
• Risk of uncontrolled bleeding during travel is significant and may require emergency intervention unavailable during flight 1

Postpartum Management

• Close hemodynamic monitoring for at least 24 hours
• Vigilance for delayed hemorrhage
• Monitor for signs of end-organ damage
• Evaluate and treat anemia with iron supplementation as needed 1

Common Pitfalls to Avoid

1. Inadequate follow-up of placenta previa diagnosed early in pregnancy (may resolve with uterine growth) 1
2. Attempting digital vaginal examination in patients with known placenta previa 6
3. Forced placental removal when accreta is encountered 1
4. Routine use of preoperative arterial catheterization or balloons (may cause complications) 1
5. Delaying delivery beyond 36 weeks (approximately 50% of women with placenta accreta spectrum beyond 36 weeks require emergent delivery for hemorrhage) 2

By following this structured approach to the management of placenta previa, maternal and fetal outcomes can be optimized through careful planning, appropriate timing of delivery, and preparation for potential complications.