Accuracy of Ultrasound in the Prediction of the FIGO Classification of Placenta Accreta Spectrum

To evaluate the accuracy of greyscale ultrasound (US) and colour Doppler detecting placenta accreta spectrum (PAS) based on the newly recommended International Federation of Obstetrics and Gynaecology (FIGO) grading system.

This prospective study was conducted on women diagnosed with placenta previa or low-lying placenta involving the anterior uterine wall and associated with PAS as identified by the US. Transabdominal and transvaginal greyscale US was performed on admission between 34 and 36 weeks of gestation and compared to clinical grading and histopathological examination after cesarean hysterectomy.

In total, 36 pregnant females who underwent a cesarean hysterectomy due to placenta previa complicated by PAS were included in this study. All patients had a history of previous cesarean deliveries, ranging from 1 to 5 deliveries. The US has an overall sensitivity of 33%, 55%, and 84.62%, and specificity of 100%, 75%, and 60% in detecting the 3 degrees of PAS, respectively. US cannot differentiate between the different subtypes of PAS grade 3 (a, b, and c).

The overall US evaluation was highly significant in predicting the FIGO diagnosis of PAS; however, all ultrasonographic signs were equally relevant in diagnosing grade 1 and/or 2 PAS and were inaccurate in differing the subtypes of PAS grade 3.