Doppler ultrasonographic features of the developing placental circulation: Correlation with anatomic findings

Color Doppler was used to study the placental circulations of 28 pregnancies between 10 and 17 weeks' gestation. A histomorphometric investigation was performed on placental tissue samples from those pregnancies, and the results were compared with Doppler features. Important changes were found around 14 weeks' gestation in both uterine and umbilical circulations. The appearance of end-diastolic frequencies in the umbilical arteries was related to an abrupt and significant (p less than 0.005) increase in uterine velocity and to the establishment of a continuous intervillous circulation.