EP16.46: Using transvaginal and transabdominal ultrasound together improves the accuracy of evaluating prenatal placenta accreta spectrum severity

This study aimed to evaluate the accuracy of prenatal transvaginal (TVS) used together with transabdominal ultrasound (TAS) to assess the severity of placenta accreta spectrum (PAS) compared with routine TAS only in women with placenta previa suspicious of PAS. A retrospective study was done between January 2020 and February 2024 in the major tertiary hospital and PAS Center in southern Thailand. The ultrasound pictures and VDO clips of women with placenta previa suspicious of PAS in the third trimester were included to evaluate the prenatal severity of PAS and then compare the findings with intraoperative grading by FIGO. The diagnostic accuracy to predict the severity of PAS between TAS alone and TVS adding on TAS has been evaluated and compared. There were 80 cases included in the study with 76 cases of PAS confirmed by intraoperative findings and pathology. In the PAS group, 14 (17.5%) were accreta, 30 (37.5%) were increta and 21 (26.3%) were percreta. In this group, 63 (78.8%) underwent hysterectomy while 2 (2.5%) underwent conservative surgery. The accuracy of TVS together with TAS was higher overall than TAS alone, 97.1% versus 94.3%, respectively. The overall accuracy to predict the severity of PAS was higher when combining TVS with TAS versus TAS only, accreta 94.3% vs 77.1%, increta 80% vs 64.3%, and percreta 80% vs 72.9%, respectively. The diagnostic performance to predict the chance of hysterectomy vs conservative surgery was higher when using TVS with TAS than TAS alone, 94.3% vs 82.9%, respectively. TVS together with TAS to evaluate the severity of PAS not only increased the overall diagnostic accuracy of specific PAS diagnoses, but also increased the accuracy of predicting the severity of PAS prenatally, which in turn helped in choosing the appropriate PAS management, either conservative surgery of Caesarean hysterectomy. Routine assessment of PAS using TVS with TAS should be encouraged.