Correlation between reduced amniotic fluid volume and Doppler spectra of fetal blood vessels at term

: The aim of this study was to determine, whether foetuses with reduced amniotic fluid in other-wise uncomplicated pregnancies at term show signs of redistribution of blood flow analogous to foetuses with intrauterine growth retardation. In 33 pregnancies > or = 37 gestational weeks with the largest pocket of amniotic fluid < 2 cm, flow velocity waveforms were recorded for the umbilical artery, middle cerebral artery and renal artery and compared with those of foetuses of the same gestational age and normal amniotic fluid volume. No difference was found in the resistance index (umbilical artery and middle cerebral artery), the pulsatility index (renal artery), or for the cerebral-placental ratio between these two collectives. We conclude, that Doppler examination of foetal vessels does not help to clarify the phenomenon of decreasing amniotic fluid volume during the final period of gestation. We suggest, that the decrease is not caused by renovascular changes, but has intra- or extrarenal causes.