(895) First and third trimester ultrasound markers for prediction of placenta accreta spectrum & clinical outcomes

Friday, January 31, 2025

10:30 AM – 12:30 PM

Submitting Author and Presenting Author(s)

Rebecca Horgan, MD

Assistant Professor
Macon & Joan Brock Virginia Health Sciences Eastern Virginia Medical School at Old Dominion University
Norfolk, VA, United States

Coauthor(s)

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Elizabeth Miller, MD

PGY-4 Resident
Macon & Joan Brock Virginia Health Sciences Eastern Virginia Medial School at Old Dominion University
Norfolk, Virginia, United States
Yara Hage Diab, MD

Research Fellow/Resident physician
Macon & Joan Brock Virginia Health Sciences Eastern Virginia Medical School at Old Dominion University
Norfolk, Virginia, United States
Juliana Martins, N/A (she/her/hers)

Associate Professor for Maternal Fetal Medicine
Macon & Joan Brock Virginia Health Sciences Eastern Virginia Medial School at Old Dominion University
Virginia Beach, Virginia, United States
George R. Saade, MD (he/him/his)

Professor and Chair, Associate Dean for Women's Health Obstetrics and Gynecology
Macon & Joan Brock Virginia Health Sciences Eastern Virginia Medical School at Old Dominion University
Norfolk, Virginia, United States
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Camille Kanaan, MD

Professor
Macon & Joan Brock Virginia Health Sciences Eastern Virginia Medical School at Old Dominion University
Norfolk, Virginia, United States
Jerri A. Waller, MD (she/her/hers)

Assistant Professor
Macon & Joan Brock Virginia Health Sciences Eastern Virginia Medical School at Old Dominion University
Norfolk, Virginia, United States

Objective: To evaluate the predictive accuracy of ultrasound markers for placenta accreta spectrum (PAS) and associated clinical outcomes in patients with prior cesarean delivery and placenta previa.

Study Design: This retrospective cohort study included patients with prior cesarean delivery and placenta previa who received prenatal care at our tertiary center from Jan 2015 to June 2022. Ultrasound markers evaluated in the first and third trimester included lacunae presence/count, bladder wall interruption, loss of retroplacental clear zone, bridging vessels, and parametrial vascularization. Ultrasounds were reviewed blindly by an MFM physician. Primary outcome was PAS and secondary outcomes included PAS severity (accreta, increta, percreta), visceral injury during surgery (bladder, ureter, bowel), and severe blood loss (EBL >1000 mL or blood transfusion). Shallow gradient booster models assessed prediction model performance with area under the curve (AUC) values and feature importance plots.

Results: Of 111 pregnancies, the final diagnosis was PAS in 33 and placenta previa without PAS in 78. Third-trimester ultrasound markers were highly predictive of PAS (AUC: 0.92, 95% CI: 0.86-0.98) vs. first-trimester markers (AUC: 0.79, 95% CI: 0.63-0.93) (P=0.047). The most predictive feature of PAS severity was bridging vessels, followed by loss of clear zone. Increta or percreta diagnosis rates were 34.4% (both features present), 18.2% (one feature), and 4.4% (absent). Visceral injury prediction was highest with loss of clear zone, followed by bridging vessels: 21.9% (both present), 18.2% (one), 2.9% (absent). Severe blood loss predictors were bridging vessels and parametrial vascularization: 89.7% (both present), 82.1% (one), 44.4% (absent).

Conclusion: Third-trimester ultrasound is an excellent predictor of PAS diagnosis. PAS ultrasound features vary in predictive potential for clinical outcomes. Top predictors of PAS severity, visceral injury, and severe blood loss are bridging vessels, loss of clear zone, and parametrial vascularization.