Pulsations in the umbilical vein during labor are associated with increased risk of operative delivery for fetal distress.

OBJECTIVES

Under physiological conditions the blood flow velocity waveform in the umbilical vein (UV) has an even non-pulsating pattern. Pulsations in the UV have been described in human fetuses exposed to chronic hypoxia and heart failure. Current techniques for fetal surveillance during labor and delivery involve a risk of both over- and underestimation of fetal hypoxia. We aimed to examine whether pulsations in the UV appear in the human fetus during suspected intrapartum hypoxia, and if so whether they are associated with increased risk of operative delivery for fetal distress (ODFD).

METHODS

This was a prospective double blind study including 52 normal pregnancies. A Doppler examination of the UV was performed on 26 fetuses with pathological and 26 fetuses with normal cardiotocography (CTG) during labor. Presence or absence of pulsations in the UV were noted and related to perinatal outcome.

RESULTS

Pulsations in the UV were seen in eight (30.8%) of the fetuses with pathological CTG, of which six (75%) underwent ODFD. No pulsations were seen in the other 18 (69.2%) fetuses with pathological CTG and these were all delivered without ODFD. No pulsations were seen in the UV in the fetuses with normal CTG and these were all delivered without ODFD. Among the fetuses with pathological CTG, there was an increased risk of ODFD in fetuses with vs. those without pulsations in the UV (P < 0.0001).

CONCLUSIONS

Pulsations in the UV can be observed in human fetuses during suspected intrapartum hypoxia and these pulsations are associated with an increased risk of ODFD. Doppler examination of the UV might give important additional information on fetal condition during labor and delivery.