Risk factors of massive blood transfusion (MTP) in cesarean hysterectomy for placenta accreta spectrum

Background: Placenta Accreta Spectrum (PAS) represents a particularly morbid condition for which blood transfusion is the leading cause. Delivery by cesarean hysterectomy is recommended for the management of PAS. Massive Transfusion Protocols (MTP) in obstetrics vary in definition and implementation. Given the significant blood loss during PAS cesarean hysterectomy, this is particularly important for surgeons and blood banks. Our objective was to identify risk factors for MTP in patients with antenatally suspected PAS.Methods: We performed a case-control study over a 11-year period from 2012 to 2022 at our center for Placenta Accreta Spectrum. MTP was defined by two methods, >4 units or > 10 units of red blood cells/whole blood transfused over 24 h. Antenatal, operative and post-operative outcomes were obtained from electronic medical records of these cases.Results: During the study time frame, 142 cases were managed by our PAS team and met all criteria. 85 % (120/ 142) of patients were transfused at least 1 unit of blood, 64 patients (45 %) received 0-3 units of blood, 50 patients (35 %) received 4-9 units of blood and 28 patients (19.7 %) were transfused > 10 units of blood. Pre -delivery vaginal bleeding, preterm labor and delivery < 34 weeks were independently significant in transfused patients. ROC analysis revealed an area under the curve (AUC) of 0.79 (p < 0.0001) in patients transfused > 10 units, showing predictive capability for this subgroup.Discussion: We here report pre-operative risk factors for MTP in patients undergoing cesarean hysterectomy for PAS. This allows for both resource utilization and patient counseling for this morbid maternal condition.