What is the management for placenta previa?

Management of Placenta Previa

The management of placenta previa requires a coordinated multidisciplinary approach with planned cesarean delivery at 36 weeks after confirming fetal lung maturity, with hospitalization for active bleeding cases and careful avoidance of digital pelvic examinations. 1

Diagnosis and Classification

• Placenta previa is diagnosed when the placenta overlies the internal cervical os, occurring in approximately 0.4% of pregnancies in the third trimester 1
• Transvaginal ultrasound is the diagnostic modality of choice for accurate assessment of placenta previa 1
• Digital pelvic examination must be avoided until placenta previa has been excluded to prevent triggering hemorrhage 2, 1
• While placenta previa is common in early pregnancy (42.3% at 11-14 weeks, 3.9% at 20-24 weeks), most cases resolve by 28 weeks 1

Risk Assessment

• Women with placenta previa and prior cesarean deliveries should be evaluated for placenta accreta spectrum disorder, which significantly increases morbidity 2, 1
• The risk of placenta accreta spectrum disorder increases 7-fold after one prior cesarean delivery to 56-fold after 3 cesarean deliveries 2
• Women with one episode of bleeding may be at increased risk for subsequent bleeding episodes 1
• Additional risk factors include advanced maternal age, high gravidity or parity, in vitro fertilization, prior uterine surgery, prior postpartum hemorrhage, Asherman syndrome, uterine anomalies, smoking, and hypertension 2

Antepartum Management

• For asymptomatic placenta previa before 28 weeks, women can continue moderate-to-vigorous physical activity 1
• After 28 weeks, women with placenta previa should avoid moderate-to-vigorous physical activity but can maintain activities of daily living and low-intensity activity such as walking 1
• Hospitalization is recommended for women with active bleeding 1, 3
• For stable patients without bleeding, outpatient management may be considered after initial stabilization, which can reduce hospital stay (average 10.1 days vs. 28.6 days for inpatient management) 3
• Optimize hemoglobin values during pregnancy; treat anemia with oral or intravenous iron as needed 1
• Administer antenatal corticosteroids when preterm delivery is anticipated 3
• Serial ultrasound evaluations should be performed to assess fetal growth and placental location 3

Delivery Planning

• Delivery should take place at an institution with adequate blood banking facilities and multidisciplinary expertise 1
• Preoperative coordination with anesthesiology, maternal-fetal medicine, neonatology, and expert pelvic surgeons is essential 1
• Notify blood bank in advance due to frequent need for large-volume blood transfusion 1
• The American Congress of Obstetricians and Gynecologists (ACOG) recommends planned cesarean delivery at 34-38 weeks depending on the severity of placenta accreta spectrum disorder if present 2
• For uncomplicated placenta previa, delivery at 36 weeks after confirming fetal lung maturity is appropriate 3, 4

Intraoperative Management

• The most accepted approach is cesarean delivery with careful surgical planning 1
• Consider dorsal lithotomy positioning to allow access to vagina and optimal surgical visualization 1
• Inspect the uterus after peritoneal entry to determine placental location and optimize uterine incision approach 1
• When possible, make the uterine incision away from the placenta 1
• After delivery of the fetus, leave the placenta in situ if there is evidence of abnormal placental attachment 1
• Attempts at forced placental removal can result in profuse hemorrhage and should be avoided 1
• In cases with high risk of hemorrhage, prophylactic intraoperative uterine artery embolization may be considered, which has been shown to reduce intraoperative blood loss (693 ml vs. 1431 ml in conventional approach) 5

Special Considerations

• For partial placenta previa in carefully selected cases, vaginal delivery may be considered, though this is not standard practice 6
• For cases with suspected bladder involvement, consider ureteric stent placement and collaboration with urologic surgeons 1
• In cases of placenta accreta spectrum disorder, cesarean hysterectomy may be necessary 2, 1
• A contingency plan for emergent delivery should be in place, as patients with placenta previa are at increased risk of prepartum hemorrhage as gestational age increases 2

Management of Complications

• Keep patients warm (>36°C) during surgery as many clotting factors function poorly at lower temperatures 2
• In cases of excessive blood loss (≥1,500 ml), re-dose prophylactic antibiotics 2
• Baseline laboratory assessment at the initiation of bleeding should include platelet count, prothrombin time, partial thromboplastin time, and fibrinogen levels 2
• When transfusing in the setting of acute hemorrhage, transfuse packed red blood cells, fresh frozen plasma, and platelets in a fixed ratio 2
• Close monitoring of volume status, urine output, blood loss, and hemodynamics is critical during surgery 1

Follow-up Care

• Ensure adequate iron supplementation and follow-up of hemoglobin levels if significant blood loss occurred 1
• Intensive hemodynamic monitoring in the early postoperative period is recommended, often best provided in an intensive care unit setting 2
• Maintain vigilance for ongoing bleeding with a low threshold for reoperation if suspected 2