What is the management plan for a patient diagnosed with placenta previa?

Management of Placenta Previa

For patients diagnosed with placenta previa, management centers on transvaginal ultrasound confirmation, risk stratification for placenta accreta spectrum (especially with prior cesarean deliveries), activity modification after 28 weeks, and planned cesarean delivery at 34 0/7 to 35 6/7 weeks at a tertiary care facility equipped for massive hemorrhage. 1, 2

Diagnostic Confirmation and Initial Assessment

• Transvaginal ultrasound is the gold standard for diagnosing placenta previa with 90.7% sensitivity and 96.9% specificity 2
• Perform transabdominal ultrasound initially as screening, followed by transvaginal ultrasound for definitive assessment 2
• Never perform digital pelvic examination until placenta previa has been excluded, as this can trigger life-threatening hemorrhage 1, 2
• Measure the distance from the leading placental edge to the internal cervical os; overlap of ≥15 mm at mid-trimester predicts persistence at delivery 2

Critical Risk Stratification for Placenta Accreta Spectrum

This is the most important prognostic factor that determines surgical planning and potential for catastrophic hemorrhage.

• All women with placenta previa AND prior cesarean deliveries must be evaluated for placenta accreta spectrum disorder 1, 2
• Risk increases exponentially: 7-fold after one prior cesarean, escalating to 56-fold after three cesarean deliveries 1, 2
• 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, 2
• MRI may be helpful when ultrasound findings are concerning for accreta or in cases of posterior placenta previa 1
• Failure to diagnose placenta accreta spectrum in at-risk women can lead to catastrophic hemorrhage 2

Antepartum Management Strategy

Before 28 Weeks Gestation

• Women with asymptomatic placenta previa can continue moderate-to-vigorous physical activity 1, 2

After 28 Weeks Gestation

• Avoid moderate-to-vigorous physical activity but maintain activities of daily living and low-intensity activity such as walking 1, 2
• Women who experience one bleeding episode are at increased risk for subsequent hemorrhage 1

Active Bleeding

• Hospitalization is recommended for women with active bleeding 1, 2
• Maintain hemoglobin optimization with oral or intravenous iron supplementation 1, 2
• Baseline laboratory assessment should include platelet count, prothrombin time, partial thromboplastin time, and fibrinogen levels 1

Delivery Planning and Timing

Optimal Timing

• Planned cesarean delivery at 34 0/7 to 35 6/7 weeks of gestation is recommended for uncomplicated placenta previa 1, 2
• This timing balances neonatal complications against increased maternal bleeding risk after 36 weeks 1
• Do not delay delivery beyond 36 0/7 weeks, as approximately 50% of women with placenta accreta spectrum beyond 36 weeks require emergent delivery for hemorrhage 1, 2
• Administer antenatal corticosteroids when delivery is anticipated before 37 0/7 weeks 1

Earlier Delivery Indications

• Persistent bleeding, preeclampsia, labor, rupture of membranes, or fetal compromise require earlier delivery 1, 2

Facility Requirements

• Delivery must occur at a level III or IV maternal care facility with multidisciplinary team including maternal-fetal medicine subspecialists, pelvic surgeons, urologists, interventional radiologists, obstetric anesthesiologists, and neonatologists 1
• Blood bank must be capable of employing massive transfusion protocols 1
• Preoperative coordination with anesthesiology, maternal-fetal medicine, neonatology, and expert pelvic surgeons is essential 1, 2
• Notify blood bank in advance due to frequent need for large-volume blood transfusion 1

Intraoperative Management

Surgical Approach

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

Placental Management

• After delivery of the fetus, leave the placenta in situ if there is evidence of abnormal placental attachment 1
• Never attempt forced placental removal, as this causes profuse hemorrhage 1, 2
• For placenta accreta spectrum, the most accepted approach is cesarean hysterectomy with placenta left in situ 1

Hemorrhage Management

• Keep patients warm (>36°C) during surgery as clotting factors function poorly at lower temperatures 1
• When transfusing in acute hemorrhage, use packed red blood cells, fresh frozen plasma, and platelets in a fixed ratio 1
• In cases of excessive blood loss (≥1,500 ml), re-dose prophylactic antibiotics 1
• Consider tranexamic acid to reduce blood loss 2
• Activate massive transfusion protocol early rather than late 2

Special Considerations

• For suspected bladder involvement, consider ureteric stent placement and collaboration with urologic surgeons 1

Postoperative Care

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

Critical Pitfalls to Avoid

• Digital examination without excluding placenta previa can trigger life-threatening bleeding 2
• Failure to diagnose placenta accreta spectrum in women with placenta previa and prior cesarean deliveries can lead to catastrophic hemorrhage 2
• Delayed activation of massive transfusion protocol worsens outcomes 2
• Attempting forced placental removal in cases of abnormal placental attachment results in profuse hemorrhage 1, 2