Peak Systolic Velocity of Subplacental Blood flow as Prenatal Diagnosis of Placenta Accreta Spectrum in Patients With Anterior Placenta Previa

Placenta accreta spectrum (PAS) is a serious complication of pregnancy with maternal and fetal morbidity and mortality. Ultrasonography is a useful application in the prenatal diagnosis of PAS disorders. The main scope of this study was to assess the peak systolic velocity (PSV) of subplacental blood flow and its correlation with the clinical description of PAS disorders.

In this cross-sectional study, 60 pregnant women with persistent anterior placenta previa in the third trimester of pregnancy were examined by color Doppler and grayscale ultrasonography for the diagnosis of PAS disorders. The PSV and resistive index (RI) of the subplacental blood flow were measured by spectrum Doppler in the anterior wall of the inferior uterine segment. Eventually, the patients were followed up until delivery and the correlation between PSV, RI, and PAS disorders was assessed post-surgery.

A total of 26 (43.3%) out of 60 patients was diagnosed with PAS disorders. In cases with PAS disorders, the PSV of the subplacental blood flow was significantly higher (AUC = 0.94, 95% CI = 0.89-1.00) compared to the not affected ones. In addition, the PSV of ≥ 43.65 cm/sec with 100% specificity was determined as the optimal cut-off for the prenatal diagnosis of PAS disorders. Finally, the RI of subplacental blood flow showed no significant difference between the two groups (AUC = 0.551, 95% CI = 0.398-0.705).

Overall, the measurement of the PSV of the subplacental blood flow in patients with anterior placenta previa can increase the accuracy of the ultrasound diagnosis of PAS disorders.