CONTINUOUS-WAVE DOPPLER VELOCIMETRY OF THE MAIN-STEM UTERINE ARTERIES- THE TRANSVAGINAL APPROACH

The purpose of the study was (1) to establish the efficacy of the tran svaginal approach for continuous wave Doppler velocimetry of the main- stem uterine arteries in normal pregnancy and (2) to provide reference values for the flow velocity waveform indices of the main-stem uterin e arteries in normal pregnancy. In a cross-sectional study from 16 to 40 weeks of pregnancy, 201 healthy normal women were examined by trans vaginal continuous wave Doppler, and flow velocity waveforms were obta ined from the main branch of the uterine artery on both sides. Nomogra ms were compiled for the systolic: diastolic ratio, pulsatility index and resistance index. Values for all variables declined during the cou rse of pregnancy until 22 weeks' gestation, and then remained stable t o term. Intra- and interobserver variations were 5% and 8%, respective ly, and the examination time was < 5 min. Flow velocity waveform indic es declined during pregnancy, indicating a decrease of resistance in t he uteroplacental circulation. Our results are comparable to those obt ained transvaginally by pulsed wave Doppler, previously reported in th e literature. The transvaginal approach for continuous wave Doppler ve locimetry of the main-stem uterine arteries is a simple, quick, accura te, safe, cheap and highly reproducible method, and is therefore suita ble for evaluating the uteroplacental circulation.