Predicting postpartum hemorrhage in placenta accreta spectrum patients with prophylactic abdominal aorta balloon occlusion: a retrospective cohort study

BACKGROUND: Prophylactic abdominal aortic balloon occlusion (AABO) is a hemostasis intervention for patients with placenta accreta spectrum (PAS). However, many PAS patients with prophylactic AABO still experience postpartum hemorrhage (PPH). This study aimed to investigate the risk factors for PPH in PAS patients undergoing prophylactic AABO. METHODS: This retrospective study (2018-2024) was conducted at a tertiary hospital. PAS women undergoing prophylactic AABO before cesarean section were enrolled and divided into the PPH group and the non-PPH (NPPH) group. The clinical characteristics, ultrasound and magnetic resonance imaging (MRI) findings, and delivery outcomes were compared. The LASSO regression and multivariable logistic regression were used to identify risk factors for PPH and to construct a nomogram prediction model. RESULTS: In total, 126 women were included, of whom 56 experienced PPH (44.4%). Compared to those in the NPPH group, the PPH group had higher gravidity (P = 0.022) and parity (P = 0.002), fewer gestational weeks at cesarean (34.9 vs. 35.6, P = 0.026), higher ultrasound scores (7 vs. 11, P < 0.001) and MRI-based PAS grades (P < 0.001). By integrating the results of the two regression methods, we constructed the nomogram to predict PPH risk. The ROC curve of the nomogram showed moderate discriminative ability, with an AUC of 0.749 (95% CI: 0.664-0.834). CONCLUSIONS: Prophylactic AABO does not completely prevent the occurrence of PPH. The nomogram intergrating gravidity, parity, ultrasound score and MRI-based PAS grades can assist clinicians in identifying high-risk PAS patients at an early stage, which is beneficial for the preoperative assessment.