What are the key findings and management strategies for a woman of childbearing age with a history of uterine surgery or previous placental abnormalities diagnosed with placenta percreta?

Placenta Percreta: Key Findings and Management

Diagnostic and Clinical Findings

Placenta percreta represents the most severe form of placenta accreta spectrum where placental villi invade completely through the myometrium and into surrounding organs, creating a surgical emergency with dramatically worse outcomes than lesser degrees of abnormal placentation. 1

Pathologic Characteristics

• Complete transmural invasion through the uterine wall with potential extension into bladder, bowel, parametria, or other pelvic structures 1
• Histologically confirmed by absence of decidua basalis with direct placental attachment to or through myometrium 1
• Clinical diagnosis is acceptable when histologic confirmation is unavailable, particularly in cases managed conservatively 1

Risk Factors

• Placenta previa combined with prior cesarean deliveries creates the highest risk scenario, with risk increasing from 7-fold after one cesarean to 56-fold after three cesareans 2
• Placenta previa is present in 49% of placenta accreta spectrum cases 2
• Prior uterine surgery, curettage, Asherman syndrome, advanced maternal age, and multiparity 1

Imaging Findings

• Ultrasound remains the primary screening modality with MRI used as supplemental imaging when ultrasound is inconclusive 2
• Loss of the normal hypoechoic retroplacental zone, placental lacunae, bladder wall interruption, and increased vascularity on Doppler 2
• MRI demonstrates uterine bulging, heterogeneous signal intensity within placenta, and direct visualization of organ invasion 3, 4

Clinical Outcomes and Complications

Maternal Morbidity Profile

Placenta percreta carries an 86.3% rate of severe maternal morbidity compared to only 26.7% for placenta accreta, making it a fundamentally different and more dangerous condition. 5

• Massive hemorrhage requiring transfusion of >10 units of packed red blood cells occurs in 40% of cases 6
• Hysterectomy rate of 84.3% even with optimal management at referral centers 5
• Ureteral injury or fistula formation in 5% each 6
• Infection and febrile morbidity in 28% 1, 6
• Maternal mortality of 1.4-7% depending on management setting 4, 6
• Uterine rupture, acute kidney injury, cardiovascular failure, and septic shock 6, 5

Expectant Management Outcomes (When Attempted)

• 44% failure rate requiring hysterectomy in percreta cases versus only 7% in lesser degrees of abnormal placentation 1
• 17% severe adverse complication rate (sepsis, organ failure, death) compared to 5% in non-percreta cases 1
• Primary failures (within 24 hours) and delayed failures (>24 hours) both occur, predominantly from hemorrhage 1
• Median time to placental involution of 13.5 weeks in successful cases 1
• 70% of severe morbidity cases occur in the delayed hysterectomy group 1

Management Strategy

Immediate Actions for Acute Presentation

If a patient with placenta percreta presents with vaginal bleeding, immediate referral to a Level III or IV maternal care facility with direct departmental communication is mandatory to reduce mortality. 7

• Establish large-bore IV access and begin crystalloid resuscitation 7
• Type and crossmatch blood immediately; activate massive transfusion protocol if significant bleeding present 7
• Obtain baseline labs: CBC, coagulation panel, fibrinogen, platelet count 7
• Maintain maternal temperature >36°C as clotting factors function poorly below this threshold 7
• Consider tranexamic acid 1 gram IV over 10 minutes if hemorrhage is ongoing 7
• Never perform digital cervical examination as this can trigger catastrophic hemorrhage 7

Planned Delivery Protocol

The gold standard is planned cesarean hysterectomy at 34 0/7 to 35 6/7 weeks gestation with the placenta left in situ, performed at a Level III or IV maternal care facility with a multidisciplinary team. 2, 8

Timing Rationale

• Decision analysis demonstrates 34 weeks is optimal, balancing neonatal outcomes against maternal hemorrhage risk 8
• 50% of women beyond 36 weeks require emergent delivery for hemorrhage, driving the recommendation for early delivery 2, 8
• Do not wait beyond 36 0/7 weeks in stable patients 8

Multidisciplinary Team Requirements

• Maternal-fetal medicine specialists 8
• Gynecologic oncology or female pelvic medicine surgeons experienced in complex pelvic dissection 8, 6
• Obstetric anesthesiologists with massive transfusion experience 8
• Interventional radiology (available but not routinely used) 8
• Blood bank with massive transfusion protocol capability 8
• Neonatology and ICU capabilities 8

Preoperative Optimization

• Coordinate massive transfusion protocol with blood bank 8
• Aggressively treat iron deficiency anemia with oral iron, IV iron infusions, or erythropoietin-stimulating agents 8
• Consider preventive catheterization of descending aorta via transhumeral access in select high-risk cases 9
• Consider ureteral stent placement when bladder invasion is suspected 4

Surgical Technique

Critical surgical principles: deliver the fetus through a uterine incision that avoids the placenta when possible, ligate the umbilical cord close to the placenta, and proceed directly to hysterectomy without attempting placental separation. 8

• Never attempt manual placental removal as this causes catastrophic hemorrhage 7, 8
• Have massive transfusion protocol activated and ready before incision 8
• Consider intraoperative cystoscopy and careful transvaginal ultrasound to determine extent of invasion into surrounding organs 4
• In cases with extensive bladder or parametrial involvement, consider intraoperative uterine artery embolization combined with tranexamic acid 4

Hemorrhage Management

• Transfuse in 1:1:1 ratio (packed RBCs:FFP:platelets) 8
• Monitor fibrinogen levels closely 8
• Consider tranexamic acid to reduce blood loss 8
• Maintain maternal temperature >36°C for optimal clotting factor function 8

Conservative Management (Investigational)

Conservative management leaving the placenta in situ is investigational and carries substantial risks, but may be considered when extensive organ involvement makes primary hysterectomy prohibitively dangerous. 1, 4

Selection Criteria

• More frequently chosen when placenta extends into bladder or gastrointestinal tract (69% vs 31% when confined to uterus) 6
• Hemodynamically stable patients 6
• Requires extensive counseling about 22-44% hysterectomy rate and infection risks 1, 8

Conservative Management Outcomes

• 22-42% still require hysterectomy 1, 8
• 28% develop infection or febrile morbidity 1, 8
• 6% experience severe morbidity including sepsis, organ failure, or death 1, 8
• Associated with less immediate blood loss (median 0 vs 7 units transfused) 6

Adjunctive Measures to Avoid

• Methotrexate is not recommended given unproven benefit and potential for severe toxicity including maternal death from septic shock 1
• Methotrexate targets rapidly dividing cells but third trimester placental cell division is limited 1
• Contraindicated in breastfeeding due to neonatal morbidity 1

Planned Delayed Hysterectomy

• Consider planned delayed hysterectomy at approximately 4 weeks from cesarean delivery in stable patients when primary hysterectomy is unsafe 4
• Hysteroscopic resection of persistent placental tissue may be attempted, though often requires multiple procedures 1

Postoperative Care

• Plan for potential ICU monitoring given risks of ongoing bleeding, fluid overload, and renal failure 8
• Maintain low threshold for reoperation if ongoing bleeding suspected 8
• Monitor for delayed complications including infection and thromboembolic events 8
• Consider anticoagulation if pulmonary embolism occurs, as amniotic fluid embolism may complicate percreta cases 3

Critical Pitfalls to Avoid

• Never attempt manual placental removal - this causes profuse hemorrhage 7, 8
• Do not delay delivery beyond 36 weeks in stable patients 8
• Do not deliver at a facility without massive transfusion capability 8
• Do not delay transfer waiting for the patient to "stabilize" unless in active hemorrhagic shock requiring immediate intervention 7
• Do not pursue conservative management without extensive counseling about the 44% hysterectomy rate specific to percreta 1
• Do not assume conservative management has the same success rate as in lesser degrees of abnormal placentation - percreta has a fundamentally worse prognosis 1, 5