What is the management for a patient with placenta previa?

Management of Placenta Previa

Planned cesarean delivery at 34 0/7 to 35 6/7 weeks of gestation is the recommended management for stable patients with placenta previa, with delivery taking place at an institution equipped for massive transfusion and multidisciplinary surgical expertise. 1

Diagnostic Confirmation and Initial Assessment

• Transvaginal ultrasound is the gold standard for diagnosis, with sensitivity of 90.7% and specificity of 96.9%, and should follow initial transabdominal screening 1
• Never perform digital pelvic examination until placenta previa has been excluded, as this can trigger catastrophic hemorrhage 1, 2
• Evaluate placental cord insertion site during the 20-week anatomy scan to identify velamentous insertion and potential vasa previa 2

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 increases surgical morbidity 1

• Risk increases 7-fold after one prior cesarean delivery and 56-fold after three cesarean deliveries 1
• Additional risk factors include advanced maternal age, high parity, prior uterine surgery, prior postpartum hemorrhage, Asherman syndrome, uterine anomalies, smoking, hypertension, and in vitro fertilization 1
• MRI may be helpful when ultrasound findings are concerning for accreta or in cases of posterior placenta previa or suspected percreta 1

Antepartum Management

Activity Restrictions

• Before 28 weeks: Women with asymptomatic placenta previa can continue moderate-to-vigorous physical activity 1
• After 28 weeks: Avoid moderate-to-vigorous physical activity but maintain activities of daily living and low-intensity walking 1

Hospitalization Criteria

• Admit for active bleeding and maintain hospitalization until bleeding stabilizes 1
• Women with one bleeding episode are at increased risk for subsequent episodes 1

Optimization

• Optimize hemoglobin values throughout pregnancy with oral or intravenous iron as needed 1
• Administer antenatal corticosteroids when delivery is anticipated before 37 0/7 weeks 1

Delivery Timing

The optimal delivery window is 34 0/7 to 35 6/7 weeks for uncomplicated placenta previa to balance maternal hemorrhage risk against neonatal prematurity 1

• Do not wait beyond 36 0/7 weeks, as approximately 50% of women with placenta accreta spectrum beyond 36 weeks require emergent delivery for hemorrhage 1
• Earlier delivery is indicated for persistent bleeding, preeclampsia, labor, rupture of membranes, or fetal compromise 1
• Have a contingency plan for emergent delivery as hemorrhage risk increases with advancing gestational age 1

Preoperative Planning

Coordinate preoperatively with anesthesiology, maternal-fetal medicine, neonatology, and expert pelvic surgeons 1

• Notify blood bank in advance due to frequent need for large-volume transfusion 1
• Consider ureteric stent placement and urologic surgeon availability if bladder involvement is suspected 1
• Obtain baseline laboratory assessment including platelet count, prothrombin time, partial thromboplastin time, and fibrinogen levels 1

Intraoperative Management

Surgical Approach

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

Management of Placenta Accreta Spectrum

• After fetal delivery, leave the placenta in situ if there is evidence of abnormal placental attachment 1
• Never attempt forced placental removal, as this results in profuse hemorrhage 1
• Cesarean hysterectomy is necessary in the majority of cases with significant placenta accreta 1, 3

Hemorrhage Management

• Keep patient temperature above 36°C, as clotting factors function poorly at lower temperatures 1
• Transfuse packed red blood cells, fresh frozen plasma, and platelets in a 1:1:1 to 1:2:4 ratio during acute hemorrhage 1
• Re-dose prophylactic antibiotics if blood loss exceeds 1,500 mL 1
• Closely monitor volume status, urine output, blood loss, and hemodynamics throughout surgery 1

Postoperative Care

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

Critical Pitfalls to Avoid

• Failure to diagnose placenta accreta spectrum in women with placenta previa and prior cesarean deliveries can lead to catastrophic hemorrhage 1
• Attempting vaginal delivery in complete placenta previa results in severe maternal hemorrhage 3
• Performing digital examination without excluding placenta previa or vasa previa can trigger vessel rupture and hemorrhage 1, 2