Reproducibility of ductus venosus Doppler flow measurements at 11-14 weeksof gestation

Objectives To assess the intra- and interobserver repeatabilities of fetal ductus venosus Doppler measurements at 11-14 weeks of gestation. Design Flow velocity waveforms were recorded transabdominally. Intraobserve r repeatability was studied in 22 fetuses in whom four repeated measurement s were performed by the same observer. Interobserver repeatability was asse ssed in 54 fetuses in each of whom two observers performed two repeated mea surements. The pulsatility index for veins (PIV), peak velocity during vent ricular systole (S wave), peak velocity during atrial contraction (A wave) and time-averaged maximum velocity (TAMV) were recorded. Reproducibility of the Doppler measurements was analyzed by calculating repeatability coeffic ient, coefficient of variation (CV), intraclass correlation coefficient (IC C), mean differences and their limits of agreement. Cohen's k-coefficient w as used for categorical data. Results Intraobserver repeatability was good with a CV of 10%, 13%, 22% and 13% and an ICC of 0.85, 0.94, 0.94 and 0.95, respectively, for PIV S wave, A wave and TAMV. Interobserver repeatability was also good, and no bias be tween the observers was detected. A CV of 8.8%, 14%, 27% and 15% and an ICC of 0.86, 0.84, 0.87 and 0.84, respectively, for PIV, S wave, A wave and TA MV were obtained. There was 100% agreement for the detection of normal/abno rmal blood flow. Conclusions Intra- and interobserver repeatability of all parameters was ac ceptable, allowing for the detection of moderate to large changes in Dopple r measurements.