Longitudinal reference intervals for ductus venosus Doppler indices

To perform a longitudinal investigation to establish reference intervals for repeated measurements for ductus venosus indices in women in weeks 15-40 of pregnancy. Ductus venosus Doppler investigation was performed by inviting the pregnant women included in the study for ultrasonography once every four weeks. Several indices were designated in order to define ductus venosus wave form, using peak velocity atrial contraction (a), systolic peak velocity (S) and diastolic peak velocity (D) values. The association between ductus venosus S, A, and D flow rates (Vs, Vd Va) and the S/A, PVIV and PLI indices calculated using these parameters and week of pregnancy was then investigated. Va and PLI exhibited a significant correlation with gestational weeks and increased with gestational age (p? 0.05). S/A and PVIV indices decreased significantly with week of pregnancy (p? 0.05) Ductus venosus measurements being performed near the central part of the vein elicited lower absolute flow rates. This resulted in different reference intervals to those of other studies for these designated parameters.