MRI-Derived Uterine Sector 2 Placental Area and Cervical Area Are Associated with Massive Hemorrhage in Complete Placenta Previa with Placenta Accreta Spectrum

Background: Placenta accreta spectrum (PAS) is an obstetric complication related to severe maternal morbidity and mortality, magnetic resonance imaging (MRI) can predict the bleeding risk and the adverse outcomes of the maternal caesarean section in PAS patients. The aim of the current study was to determine relationship of placenta area in sector 2 (S2) and cervical area measured by MRI with massive hemorrhage (MH) in complete placenta previa patients with PAS. Methods: One hundred and thirty-eight patients were diagnosed as PAS from January 2016 to December 2023 in the retrospective study. The patients were divided into two groups according to the estimated blood loss volume: MH group (estimated blood loss > 2000 mL) and non-MH group (estimated blood loss ≤ 2000 mL). After adjusting for PAS grade and clinical variables, the correlation between placenta area in S2, cervical area and MH were evaluated with multivariate analysis. The evaluation capabilities of indicators were assessed using receiver operating characteristic (ROC) analysis. Results: The placenta area in S2 of the MH group was significantly higher than that of the group without MH ( P < 0.001), on the contrary, cervical area was significantly lower in PAS patients with MH than that of the group without MH ( P < 0.001). After adjusting for the type of PAS, a placenta area in S2 ≥ 45 cm 2 (OR, 4.805; 95% CI, 2.776– 8.794; P < 0.05) and a cervical area < 4.0 cm 2 (OR, 4.015; 95% CI, 1.905– 7.862; P < 0.05) were independently associated with an increased risk of MH. A positive association was found between the placental area and the amount of blood loss (r=0.748), and negative linear was found between the cervical area and the amount of blood loss (r=− 0.682), between cervical area and placenta area (r=− 0.575). Combined with placental area in S2 and cervical area, the sensitivity, specificity, and the area under the curve (AUC) for the predictive MH were 89.237%, 91.548%, and 0.910 (95% CI 0.858 ~ 0.963), respectively. Conclusion: The placenta area in S2 and cervical area measured by MRI show potential utility in identifying MH among patients with PAS, which may assist in preoperative risk stratification. These preliminary results require validation in future studies.