Abstract: Objective： To evaluate the value of color Doppler ultrasound in the diagnosis of placenta accreta. Methods：Retrospective analysis of 93 cases diagnosed as placenta low state，low-lying placenta or placenta previa through ultrasound examination in our hospital between January 2012 to October 2013. 24 cases were diagnosed as placenta implantation among them. Abdominal and transvaginal ultrasonography focus in observing the thickness，position and internal echo of the placenta，the thickness of uterine muscle in placental site，the relationship between the placenta and uterine muscle，and the adjacent urinary bladder wall blood flow in placental site were also included. Results：24 patients were suspected of placenta implantation by color Doppler ultrasonography，20 cases were confirmed of placenta implantation by pathology after operation，including 4 cases of placenta adherence，14 cases of placenta accreta，2 cases of placenta penetration.，5 cases of misdiagnosis, missed diagnosis in 1 cases. Sensitivity and specificity of color Doppler ultrasonography was 95.00% and 93.15% respectively. The positive predictive value and the negative predictive value of color Doppler ultrasonography was 79.17% and 98.55% respectively. Conclusions：The color Doppler ultrasound is a preferred method for prenatal diagnosis of placenta accreta.

Key words: Placenta accreta, Ultrasonography, Doppler, color, Placenta previa, Prenatal diagnosis