umbilical venous flow assessment

Umbilical venous flow in the physiological situation comprises of a monophasic non-pulsatile flow pattern in the umbilical vein with a mean velocity of 10-15 cm/s. Since a normal umbilical vein supplies a continuous forward flow of oxygenated blood to the fetal heart, the presence of pulsatility implies a pathological state unless in the following situations:

  • early in pregnancy: up to ~13 weeks gestation 
    • the presence of pulsatility may be higher in chromosomally abnormal fetuses even in early pregnancy
  • when confounded by other movement variables such as 
    • fetal breathing movement
    • fetal hiccups

Pulsations of the umbilical venous system, especially double pulsations have been associated with increase in the perinatal mortality when associated with the absent and reversed end-diastolic flow velocity in the umbilical artery.

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