BACKGROUND: Morbidly adherent placenta, also known as placenta accreta spectrum, is associated with severe maternal morbidity and mortality. Multiple adjunctive procedures have been proposed to improve outcomes, and at many institutions, interventional radiologists will play a role in assisting obstetricians in these cases. OBJECTIVE: The objective of the study was to evaluate the outcomes of women with morbidly adherent placenta who underwent cesarean hysterectomy with aortic balloon occlusion or internal iliac artery balloon occlusion catheters, compared with cesarean hysterectomy with surgical ligation of the iliac arteries, or cesarean hysterectomy without adjunctive procedures. STUDY DESIGN: A retrospective review of women with morbidly adherent placenta treated with cesarean hysterectomy was performed at 5 institutions from May 2014 to April 2018. The balloon occlusion group had either prophylactic aortic or iliac balloons placed prior to cesarean hysterectomy. Comparison groups included those who underwent internal iliac artery ligation prior to hysterectomy or a control group if they underwent cesarean hysterectomy without adjuvant procedures. Evaluated outcomes include estimated blood loss, transfusion requirements, intensive care unit admission, and adverse event rates. RESULTS: There were 171 women with morbidly adherent placenta included in the study. Twenty-eight had balloon placement prior to cesarean hysterectomy, 18 had intraoperative internal iliac artery ligation, and there were 125 control women who underwent cesarean hysterectomy without any adjunctive procedures. Compared with the women who underwent cesarean hysterectomy without adjunctive procedures, women who underwent aortic or iliac artery balloon occlusion prior to hysterectomy had significantly lower estimated blood loss (30.9% decrease, P < .001), transfusion requirements (76.8% decrease, P < .001), intensive care unit admission rates (0% vs 15.2%, P < .001), and intensive care unit stay lengths (0.0 vs 3.1 days, P < .001). Compared with women who underwent surgical ligation of the internal iliac arteries prior to hysterectomy, women who underwent aortic or iliac artery balloon occlusion prior to cesarean hysterectomy had lower estimated blood loss (54.2% decrease, P < .01), transfusion requirements (90.5% decrease, P < .001), operating room times (40.0% decrease, P < .01), intensive care unit admissions rates (0% vs 77.8%, P < .001), intensive care unit stay lengths (0.0 vs 1.4 days, P < .001), and adverse events (3.6% vs 44.4%, P < .01). CONCLUSION: Aortic and iliac artery balloon occlusion are associated with lower estimated blood loss, transfusion requirements, intensive care unit admission rates, and adverse event rates compared with women who underwent internal iliac artery ligation prior to cesarean hysterectomy or women who had no adjunctive interventions prior to cesarean hysterectomy for morbidly adherent placenta.