Uteroplacental detachment on transvaginal ultrasound is associated with substantial antepartum hemorrhage requiring early delivery in high-risk placenta accreta spectrum cases

Introduction Accurately predicting progression from mild to substantial antepartum hemorrhage requiring early delivery in patients with a high risk for placenta accreta spectrum remains a clinical challenge, limiting effective monitoring and counseling. This study aims to identify ultrasound features associated with substantial antepartum hemorrhage necessitating early cesarean delivery using a comprehensive imaging protocol. Materials and methods This was secondary analysis of a prospectively collected data of high-risk placenta accreta spectrum patients between September 2023 and August 2024 in Indonesia. A comprehensive ultrasound protocol combining transabdominal and transvaginal approaches was used to assess various ultrasound signs. Antepartum hemorrhage was classified as >/=500 mL (substantial antepartum hemorrhage) or <500 mL (mild antepartum hemorrhage). Results The study included 123 participants with low-lying placenta or placenta previa, comprising 93 (75.6%) cases of placenta accreta spectrum and 30 (24.4%) cases of nonaccreta uterine scar dehiscence. Antepartum hemorrhage occurred in 50 patients (40.6%). Of these, 19 (38%) cases with mild antepartum hemorrhage progressed to substantial hemorrhage requiring an early cesarean delivery with a median gestational age of 33 (31–35) weeks, while 31 (62%) cases proceeded with an elective cesarean delivery at a median gestational age of 36 (34–37) weeks. Within this group, uteroplacental detachment observed on transvaginal ultrasound was the only significant factor independently associated with progression to substantial hemorrhage (adjusted odds ratio, 22.4; 95% confidence interval, 2.04–246.3; P =.011), demonstrating a sensitivity of 71.0% (95% confidence interval, 55.0%–84.7%) and specificity of 88.0% (95% confidence interval, 47.0%–100%). Further time-to-event analysis using Cox regression revealed a hazard ratio of 4.03 (95% confidence interval, 1.56–10.43; P =.0041), indicating a significantly shorter interval to early cesarean delivery in affected cases. Conclusion Uteroplacental detachment identified on transvaginal ultrasound in women with placenta previa and mild antepartum hemorrhage is associated with the progression to substantial antepartum hemorrhage requiring early cesarean delivery irrespective of the presence of placenta accreta spectrum. This sign may serve as a useful marker to guide individual delivery timing, helping clinicians mitigate the risks of hemorrhage against the risks of prematurity.