Transvaginal color Doppler in the assessment of the uteroplacental circulation in normal early pregnancy.

Transvaginal color Doppler investigation of the uteroplacental circulation was performed on 108 pregnant women with normal intrauterine pregnancy. Decline of resistance index (RI) and pulsatility index (PI) and increase of peak systolic velocity (Ps velocity) were found in all segments of the uteroplacental circulation with advancing gestational age. There was a decrease of RI and PI from the uterine artery through its branches: arcuate, radial and spiral arteries. Ps velocities decreased from the uterine, through the arcuate, to the radial arteries, but Ps velocities in the spiral arteries were higher than those in the radial arteries. According to our results RI seems to be more precise in the assessment of the uteroplacental than the PI.