Association Between the Timing of Prenatal Ultrasound Detection and Hemorrhage Outcomes in Placenta Accreta Spectrum Disorders

Background: Timely and accurate prenatal diagnosis of placenta accreta spectrum (PAS) is pivotal for improving maternal and fetal outcomes. However, the timing of PAS detection and its association with outcomes have rarely been explored. This study examined the association between the gestational week at which PAS was first detected by ultrasound and the clinical characteristics and outcomes of the disorder. Methods: This retrospective cohort study included PAS patients at a tertiary referral center over a 5-year period. Patients who underwent cesarean section with prenatal PAS diagnosis were classified according to the gestational age of the earliest ultrasound PAS detection (<28 weeks or ≥28 weeks). Patient characteristics and outcomes were obtained from the inpatient medical records. Univariate and multivariate robust-error-variance Poisson regression models were used to explore the associations between the timing of ultrasound diagnosis and the risk of intraoperative hemorrhage (≥1500 mL) as well as blood-product transfusion volume (≥800 mL). Results: The study included 166 PAS patients, of whom 39.2% were diagnosed before 28 weeks, and 77.1% delivered at or beyond 34 weeks (median: 35 weeks). Patients with PAS detected before 28 weeks (early detection group) experienced significantly higher intraoperative blood loss volume (median: 1500 mL vs. 800 mL) and red blood cell transfusion volume (median: 586 mL vs. 70 mL). In regression analysis, patients in the early-detection group were significantly more likely to experience blood loss ≥1500 mL and red blood cell transfusion ≥800 mL, and these associations remained significant after adjustment for invasive PAS and hysterectomy. When ultrasound-detection weeks were divided into 6 categories, early detection (<20, 20–24, and 24–28 weeks) was associated with a significantly higher risk of excessive blood loss and increased transfusion volume. Conclusions: PAS detected during the second trimester was associated with more adverse outcomes than cases identified later, highlighting the need for tailored management strategies. The association between gestational age of PAS detection and clinical outcomes warrants further investigation at both clinical and etiological levels.