Reference ranges for flow velocities and the indices of the ductus venosus in low-risk pregnancies

Abstract

Objective: Ductus venosus blood flow velocity measurements are mandatory in many clinical indications. The evaluation of the flow is performed either by comparing results with general reference tables or by qualitative assessment of the “a” flow, in regard to reversed or absent flow in the spectral waveforms. The aim was to develop normal reference ranges in low-risk pregnancies in our population. Material and Methods: Measurements of flow velocities (S, v, D, a) and indices (pulsatility index for veins, peak velocity index for veins, a/S, S/a) were performed by a single experienced specialist in 1279 singleton, uncomplicated pregnancies between 11 and 40 weeks gestation. The absolute flow velocities (S, v, D, a, VmPeak) and indices were obtained from spectral waveforms using the equipment producer’s inbuilt system. The still images were stored in the picture archiving and communication system. Results: The predicted reference ranges of the ductus venosus blood flow velocities according to the gestational age are shown in tables and graphics. Predicted reference curves based on the 5th and 95th percentiles according to gestational week were plotted and are given in tables and figures. Conclusion: Normal reference ranges for absolute flow velocities and indices were calculated from a population of uncomplicated pregnancies attending a tertiary care center. The measurements were made from both the classic patterns of the waveforms and also considered variants of the spectral waveforms, which have recently been reported, for the first time in the medical literature.

Reference values for ductus venosus Doppler velocity indices between 11 and 13+6 weeks of gestation: A single-center prospective study in Iran

“…Our results show a non-significant decrease in DVRI over the gestation period, in agreement with every other study. [ 23 33 39 42 ] As well, the reference values found in this study resembled those estimated by previous studies. Unexpected findings regarding this index were significant negative coefficients for the 5 th and 95 th percentile regression lines across the CRL range.…”

“…Earlier studies have demonstrated nonsignificant changes within this index during the first trimester of pregnancy. [ 22 23 33 39 ] Our estimated reference ranges were much close to previous reports, a bit narrower than those of Turan et al . [ 22 ]…”

“…Therefore, fractional indices such as DVPI, DVRI, and DV S/A ratio can be reproduced with greater accuracy. [ 23 ]…”

“…As such, it is more precise and consistent than reporting waveform shapes. [ 23 ] Yet, reference values must be introduced to differentiate normal versus abnormal blood flow.…”

Left atrial shortening fraction to predict fetal cardiac abnormalities and dysfunction in gestational diabetes mellitus

“…In GDM fetuses with septal hypertrophy, increased right atrial pressure is associated with right ventricular dysfunction (22). DV blood flow spectrum showed a decreased flow velocity and an increased DV-PI in GDM fetuses (23,24).…”