Fetal redistribution of blood flow and amniotic fluid volume in growth-retarded fetuses

Our purpose was to assess the relationship between the fetal redistribution of blood flow and the amount of amniotic fluid in appropriate-for gestational-age fetuses and growth-retarded fetuses. Blood flow velocity waveforms of the umbilical artery, descending aorta, middle cerebral artery, renal artery and uterine artery were recorded using pulsed Doppler ultrasonography in 100 appropriate-for gestational age fetuses and 39 growth-retarded fetuses. The pulsatility index (PI) values and the amount of amniotic fluid were compared between the two groups. The PI values of the umbilical artery and renal artery were significantly higher in appropriate for gestational-age-fetuses with oligohydraminos than in fetuses with an adequate amount of amniotic fluid. The PI values of the umbilical artery and renal artery were significantly higher and the PI of the middle cerebral artery was significantly lower in growth-retarded fetuses with oligohydramnios than in fetuses with an adequate amount of amniotic fluid. Furthermore, there was a significant negative correlation between the PI value of the renal artery and the vertical diameter of amniotic fluid, and between the PI value of the renal artery and the amniotic fluid index. The PI value of the renal artery was related to the amount of amniotic fluid in growth-retarded fetuses, and the same relationship was demonstrated in appropriate-for gestational age fetuses.