Objective This study compares the number of units of red blood cells (RBCs) transfused in patients with placenta accreta spectrum (PAS) treated with or without a multidisciplinary algorithm that includes placental uterine arterial embolization (P-UAE) and selective use of either immediate or delayed hysterectomy. Study Design This is a retrospective study of deliveries conducted at a tertiary care hospital from 2001 to 2018 with pathology-confirmed PAS. Those with previable pregnancies or microinvasive histology were excluded. To improve the equity of comparison, analyses were made separately among scheduled and unscheduled cases, therefore patients were assigned to one of four cohorts as follows: (1) scheduled/per-algorithm, (2) scheduled/off-algorithm, (3) unscheduled/per-algorithm, or (4) unscheduled/off-algorithm. Primary outcomes included RBCs transfused and estimated blood loss (EBL). Secondary outcomes included perioperative complications and disposition. Results Overall, 95 patients were identified, with 87 patients meeting inclusion criteria: 36 treated per-algorithm (30 scheduled and 6 unscheduled) and 51 off-algorithm patients (24 scheduled and 27 unscheduled). Among scheduled deliveries, 9 (30.0%) patients treated per-algorithm received RBCs compared with 20 (83.3%) patients treated off-algorithm (p < 0.01), with a median (interquartile range [IQR]) of 3.0 (2.0, 4.0) and 6.0 (2.5, 7.5) units transfused (p = 0.13), respectively. Among unscheduled deliveries, 5 (83.3%) per-algorithm patients were transfused RBCs compared with 25 (92.6%) off-algorithm patients (p = 0.47) with a median (IQR) of 4.0 (2.0, 6.0) and 8.0 (3.0, 10.0) units transfused (p = 0.47), respectively. Perioperative complications were similar between cohorts. Conclusion A multidisciplinary algorithm including P-UAE and selective use of delayed hysterectomy is associated with a lower rate of blood transfusion in scheduled but not unscheduled cases. Key Points