FETAL RENAL PULSED DOPPLER WAVE-FORM IN PROLONGED PREGNANCIES

OBJECTIVE: Our purpose was to determine Doppler waveforms of the fetal human renal artery in prolonged pregnancy in the presence or absence of oligohydramnios. STUDY DESIGN: Fifty patients at or after 40 weeks were studied. Ultrasonography was performed to determine the amniotic fluid index by the four-quadrants technique. Two groups of patients we re obtained on the basis of the amniotic fluid index. Group 1 had an a mniotic fluid index >5 (normal) (n = 33); group 2 had an amniotic flui d index less-than-or-equal-to 5 (oligohydramnios) (n = 17). Umbilical artery and fetal renal pulsed Doppler waveforms were determined and an alyzed. The fetal renal artery systolic-to-diastolic ratio of the two groups was compared. RESULTS: Fetuses with a low amniotic fluid index had a significantly higher ratio. A significant negative correlation c oefficient between amniotic fluid index and fetal renal systolic/diast olic ratio was found (r = -0.435 and p < 0.01). CONCLUSIONS: In prolon ged pregnancies there is a significant relationship between the amniot ic fluid index and the fetal renal systolic/diastolic ratio. In pregna ncies associated with oligohydramnios the systolic/diastolic ratio is significantly higher than in those with normal amniotic fluid volume. These data suggest that intrarenal flow in prolonged pregnancies compl icated with oligohydramnios is significantly different.