What is the treatment for a pregnant patient with placenta previa?

Treatment of Placenta Previa

For placenta previa, planned cesarean delivery at 34 0/7 to 35 6/7 weeks of gestation is the definitive treatment, performed at a tertiary care facility with multidisciplinary expertise and massive transfusion capabilities. 1, 2

Immediate Diagnostic Priorities

• Avoid digital pelvic examination until placenta previa is excluded, as this can trigger life-threatening hemorrhage 1, 2
• Confirm diagnosis with transvaginal ultrasound (90.7% sensitivity, 96.9% specificity), which is safe and superior to transabdominal imaging 2
• Measure the distance from placental edge to internal cervical os; overlap ≥15 mm at mid-trimester predicts persistence at delivery 2
• Use Doppler ultrasound to identify vasa previa and assess placental blood flow patterns 2

Critical Risk Stratification for Placenta Accreta Spectrum

All women with placenta previa AND prior cesarean deliveries must be evaluated for placenta accreta spectrum disorder, as this dramatically changes surgical planning 1, 2:

• Risk increases 7-fold after one prior cesarean and 56-fold after three cesareans 1, 2
• Additional risk factors include advanced maternal age, high parity, prior uterine surgery, prior postpartum hemorrhage, in vitro fertilization, smoking, and hypertension 1, 2
• MRI may be helpful for posterior placenta previa or suspected placenta percreta 1, 2

Antepartum Management Algorithm

Before 28 weeks (asymptomatic patients):

• Continue moderate-to-vigorous physical activity 1, 2
• Schedule follow-up ultrasounds at 18-20 weeks, 28-30 weeks, and 32-34 weeks to assess for resolution 2

After 28 weeks:

• Restrict to activities of daily living and low-intensity walking only 1, 2
• Hospitalize immediately for any active bleeding 1, 2

Anemia optimization throughout pregnancy:

• Maximize hemoglobin with oral or intravenous iron supplementation to prepare for potential hemorrhage 1, 2

Delivery Timing and Location

Optimal delivery window: 34 0/7 to 35 6/7 weeks of gestation 1, 2:

• Before 34 weeks: higher neonatal morbidity from prematurity 1
• After 36 weeks: approximately 50% of women with placenta accreta spectrum require emergent delivery for hemorrhage 1, 2
• Administer antenatal corticosteroids when delivery anticipated before 37 0/7 weeks 1, 2

Earlier delivery required for:

• Persistent bleeding 1
• Preeclampsia 1
• Labor or rupture of membranes 1
• Fetal compromise 1

Delivery must occur at a level III or IV maternal care facility with 1, 2:

• Maternal-fetal medicine subspecialists
• Pelvic surgeons and urologists
• Interventional radiologists
• Obstetric anesthesiologists
• Neonatologists
• Blood bank with massive transfusion protocol capabilities

Preoperative Coordination

Notify and coordinate with the following teams before delivery 1, 2:

• Anesthesiology for regional or general anesthesia planning 1, 2
• Blood bank for large-volume transfusion availability 1, 2
• Neonatology for preterm infant management 1, 2
• Urology for potential ureteric stent placement if bladder involvement suspected 1, 2

Intraoperative Management

Surgical approach:

• Inspect uterus after peritoneal entry to determine placental location 1
• Make uterine incision away from the placenta when possible 1, 2
• Consider dorsal lithotomy positioning for vaginal access and optimal visualization 1

If placenta accreta spectrum encountered:

• Leave placenta in situ - forced removal causes profuse hemorrhage 1
• Cesarean hysterectomy is the most accepted approach for confirmed placenta accreta spectrum 1, 2

Hemorrhage management protocol:

• Activate massive transfusion protocol early 2
• Transfuse packed red blood cells:fresh frozen plasma:platelets in 1:1:1 to 1:2:4 ratio 2
• Keep patient warm (>36°C) as clotting factors function poorly at lower temperatures 1
• Re-dose prophylactic antibiotics if blood loss ≥1,500 ml 1, 2
• Obtain baseline labs: platelet count, PT, PTT, fibrinogen 1, 2
• Consider tranexamic acid to reduce blood loss 2

Postoperative Management

Intensive monitoring required 1, 2:

• ICU-level hemodynamic monitoring in early postoperative period 1, 2
• Close monitoring of volume status, urine output, and ongoing blood loss 1, 2
• Low threshold for reoperation if ongoing bleeding suspected 2
• Ensure adequate iron supplementation and hemoglobin follow-up if significant blood loss occurred 1, 2

Common Pitfalls to Avoid

• Failure to diagnose placenta accreta spectrum in women with placenta previa and prior cesareans leads to catastrophic hemorrhage 1
• Delaying delivery beyond 36 weeks significantly increases emergency hemorrhage risk 1, 2
• Attempting manual placental removal when accreta encountered causes profuse bleeding 1
• Performing digital pelvic examination before excluding placenta previa can trigger hemorrhage 1, 2
• Delivering at facilities without massive transfusion capabilities increases maternal morbidity and mortality 1, 2