Preoperative predictors of blood transfusion during cesarean delivery in placenta accreta spectrum

BACKGROUND: Placenta accreta spectrum (PAS) carries substantial hemorrhagic morbidity during cesarean delivery (CD), yet clinically useful antenatal risk indicators of intraoperative hemodynamic instability remain limited. This study aimed to evaluate associations between routinely available preoperative clinical and sonographic factors and intraoperative blood transfusion. METHODS: We conducted a retrospective cohort study of all patients with PAS who underwent CD at a tertiary medical center between 2000 and 2020. Patients were stratified by whether they received intraoperative blood product transfusion. Preoperative clinical characteristics and sonographic findings were analyzed. Multivariable logistic regression was used to evaluate associations between preoperative factors and blood transfusion, with a prespecified subgroup analysis restricted to grade-1 PAS. RESULTS: Of 312 patients with PAS, 97 (40%) required intraoperative blood product transfusion. On multivariable analysis, antenatal diagnosis of placenta previa (odds ratio [OR] 4.99, 95% CI 2.55-9.92) and sonographic suspicion of PAS (OR 3.13, 95% CI 1.40-7.10) were independently associated with transfusion. In the subgroup of patients with grade-1 PAS, placenta previa remained the sole independent predictor of transfusion (OR 6.92, 95% CI 2.96-16.8). Intraoperative factors, including hysterectomy, longer operative duration, and use of general anesthesia, were more common among transfused patients and reflected surgical complexity rather than preoperative risk. CONCLUSIONS: Placenta previa and antenatal suspicion of PAS were the clinical features most strongly associated with intraoperative blood transfusion. These findings support pragmatic preoperative preparation and surgical planning in PAS management.