Objective: To compare peripartum outcomes of uterus preserving procedures to caesarean hysterectomy in women with placenta accreta spectrum (PAS), and to identify risk factors associated with adverse maternal outcomes. Design: Retrospective study (ClinicalTrials.gov identifier: NCT04384510) Setting:11 tertiary centres from 9 countries Population or Sample: women with of PAS who were managed in participating centres between January 1st, 2010 and December 31st, 2019. Women who had confirmed diagnosis with PAS with adequate documentation and follow-up, were considered eligible. Main Outcome Measures: Primary outcome was massive PAS-associated perioperative blood loss (intraoperative blood loss ≥ 2500 ml, bleeding associated massive transfusion protocol, or complicated by disseminated intravascular coagulopathy). Results: Out of 797 women, 727 were eligible for the study. Five hundred ninety-two (81.43%) women were managed by uterus preserving procedures versus 135 (18.56%) who underwent caesarean hysterectomy. After adjustment for significant or close-to-significance variables, type of management was not associated with higher risk of massive blood loss (aOR 1.71, 95% CI 0.78 - 3.81). Other factors that were significantly associated with higher risk of massive PAS-associated blood loss included body mass index, preoperative haemoglobin, centrally located placenta, diffuse placental invasion, parametrial invasion, and intrauterine foetal death. Conclusions: In the presence of sufficient experience, uterus preserving procedures may not be associated with higher risk of massive blood loss compared to caesarean hysterectomy. Funding: none