Management of Placenta Accreta Spectrum (PAS)
The recommended management for patients with placenta accreta spectrum (PAS) requires delivery at a level III or IV maternal care center with a comprehensive multidisciplinary team experienced in managing this condition to optimize maternal and fetal outcomes. 1, 2
Diagnosis and Risk Assessment
Risk factors that should trigger screening:
Ultrasound findings suggestive of PAS:
- Multiple vascular lacunae with turbulent flow
- Loss of clear space between placenta and myometrium
- Decreased retroplacental myometrial thickness (<1mm)
- Abnormalities of uterine serosa-bladder interface
- Extension of placenta into myometrium, serosa, or bladder 1
Clinical risk factors remain equally important as ultrasound findings for diagnosis, as the absence of ultrasound findings does not preclude PAS 1
Multidisciplinary Team Approach
- Assemble a team including:
- Maternal-fetal medicine specialist
- Experienced pelvic surgeon
- Anesthesiologist
- Blood bank personnel
- Interventional radiologist
- Urologist (if bladder involvement suspected) 2
Delivery Planning
Timing: Schedule delivery at 34 0/7-35 6/7 weeks of gestation in stable patients 1
Antenatal corticosteroids: Administer if delivery is planned before 37 weeks 2
Surgical Management
Standard approach: Cesarean hysterectomy with placenta left in situ 1, 2, 3
- Do not attempt to remove the placenta during delivery as this increases risk of hemorrhage
- Total hysterectomy is typically required due to lower uterine segment or cervical bleeding
Surgical technique:
- Place patient in dorsal lithotomy position
- Consider vertical skin incision or wide transverse incision
- Inspect uterus after peritoneal entry
- Make uterine incision away from placenta when possible
- Deliver fetus without disturbing placenta 2
- Consider ureteric stent placement if bladder involvement is suspected 2
Blood Management
- Implement massive transfusion protocol with a ratio of 1:1:1 to 1:2:4 (packed red cells:fresh frozen plasma:platelets) 1, 2
- Monitor and maintain fibrinogen levels >200 mg/dL
- Consider tranexamic acid (1g IV) within 3 hours of delivery, repeating after 30 minutes if bleeding persists
- Utilize cell salvage if available, with leucocyte depletion filter for autotransfusion 2
Conservative Management Considerations
- Conservative management (removing placenta without hysterectomy) or expectant management (leaving placenta in situ without hysterectomy) should be considered only for carefully selected cases 1
- These approaches are considered investigational with uncertain efficacy
- Appropriate only for cases with focal placental adherence
- Requires detailed counseling about risks
- Contraindicated in the presence of sepsis due to high risk of septic shock and maternal mortality 2
Postoperative Care
- Intensive hemodynamic monitoring in ICU setting
- Vigilance for ongoing bleeding
- Broad-spectrum antibiotic coverage:
- Options include Piperacillin-tazobactam + Gentamicin or Meropenem/Imipenem + Gentamicin 2
- Serial lactate measurements to assess response to treatment
- Daily blood cultures until clearance if infection suspected
- Monitor for complications such as renal failure, liver failure, and infection 2
Outcomes and Quality Improvement
- Institutional protocols for screening and management have demonstrated improved outcomes 4
- Timely diagnosis, extensive pre and postoperative counseling, and multidisciplinary teamwork ensure reduced early and late morbidity 4
Pitfalls and Caveats
- Undiagnosed cases have significantly worse outcomes; maintain high index of suspicion with risk factors
- Attempting placental removal in PAS cases dramatically increases hemorrhage risk
- Delayed surgical intervention in cases of sepsis increases mortality risk
- Inadequate initial antibiotic coverage is associated with increased mortality in septic cases 2
- Interobserver variation in ultrasound interpretation may affect diagnosis; clinical risk factors remain crucial 1