Antenatal diagnosis of placenta previa accreta in patients with previous cesarean scar

Aim: To determine the accuracy of transabdominal and transvaginal gray-scale and color Doppler in diagnosing placenta previa accreta in patients with previous cesarean sections. Methods: Twenty-one patients who had undergone previous cesarean sections and were confirmed to have partial or total placenta previa in the current pregnancy were subjected to ultrasound examinations after the 28th week of gestation. Specific ultrasound features were looked for on gray-scale ultrasound and color Doppler examination of the placenta and its interphase with the uterus and the bladder. Results: Seven of the 21 patients had ultrasound evidence of placenta accreta and all were later confirmed to have placenta previa accreta intraoperatively. The gray-scale positive findings were present in six out of the seven patients. The most prominent gray scale feature to suggest placenta accreta was the presence of multiple lakes that represent dilated vessels extending from the placenta through the myometrium. All seven patients had features of placenta accreta when examined with color Doppler. The most prominent color Doppler feature present in all seven patients was the presence of interphase hypervascularity with abnormal vessels linking the placenta to the bladder. The sensitivity and specificity of antenatal ultrasound diagnosis of placenta previa accreta was 100%. Conclusion: Antenatal diagnosis of placenta previa accreta can be made with a thorough ultrasound examination of the placenta in patients with previous cesarean scar and placenta previa.