Alterations in ductus venosus velocity indices in relation to umbilical venous pulsations and perinatal outcome

Abnormal blood velocity in the ductus venosus is more frequently detected than pulsations in the umbilical vein, but both are considered to be indicators of fetal compromise. The aim of this study was to investigate blood flow patterns in the ductus venosus and the association between individual blood velocity ratios and pulsations in the umbilical vein and perinatal outcome.

Retrospective cohort study on Doppler ultrasound examination of ductus venosus and umbilical venous blood velocity in 358 high-risk pregnancies. Ductus venosus blood velocity pattern was analyzed for pulsatility index and the following velocity ratios: S/ES, S/a and ES/a (where S is systole, ES is end-systole, and a is atrial contraction). Ductus venosus ratio z-scores were calculated and related to pulsations in the umbilical vein and adverse perinatal outcome.

Systolic ratios in the ductus venosus were less frequently abnormal than ratios taking into account diastolic velocities, particularly at full-term. High S/ES, ES/a ratios and pulsatility index (z-score >2), were all related to presence of pulsations in the umbilical vein. Umbilical venous pulsations were the best indicator of adverse perinatal outcome.

Changes in ductus venosus blood flow during systole occur more rarely than diastolic changes, and alterations in end-diastolic blood velocity in the ductus venosus might give false-positive indications of worsening fetal condition. Umbilical venous pulsations seem to better predict adverse outcome of pregnancy than do indices in the ductus venosus.