Two-dimensional ultrasound signs as predictive markers of massive peri-operative blood loss in placenta previa suspicious for placenta accreta spectrum (PAS) disorder

OBJECTIVE: To evaluate certain two-dimensional (2D) ultrasound signs as predictors of massive peri-operative blood loss (PBL) in pregnant women with placenta previa suspicious of PAS disorder. MATERIALS AND METHODS: A single center retrospective study was done in pregnant women who had undergone prenatal diagnosis with 2D ultrasound grey scale and color Doppler using the EW-AIP (which has been changed to IS-PAS (International Society for the Placenta Accreta Spectrum)) criteria between January 2007 and May 2021. The patients were divided into 2 groups, non-massive hemorrhage with PBL ≤ 2500 mL and massive PBL >2500 mL. All PAS cases had pathological confirmation. Ultrasound signs and hemorrhagic outcomes were compared between the two groups. A PAS scoring system to predict massive PBL was constructed and a receiver operating characteristic (ROC) curve was calculated to evaluate the efficacy of the scoring system. RESULTS: Of 534 women, 146 (28.3%) had PBL > 2500 mL and 388 (71.7%) had PBL ≤ 2500 mL. In the massive PBL group, 101 (69.2%) were diagnosed as PAS and 45 (30.8%) as placenta previa alone. From 10 evaluated 2D ultrasound signs, 3 had the highest odds ratios (ORs) associated with massive PBL, ‘focal exophytic mass’ OR 8.17 (p = 0.024), ‘placental bulge’ OR 2.47 (p = 0.011), and ‘placental lacunae feeder vessels’ OR 2.38 (p = 0.01). When using the PAS scoring system, the AUC to predict massive PBL was 0.80 (95% CI, 0.76–0.85,). CONCLUSION: Our PAS scoring system based on 2-dimensional ultrasound signs combined with grey scale and color Doppler is useful to predict massive PBL and can help optimize pre-operative management in cases of previa suspicious of PAS.