[Evaluation of the renal artery in the fetuses with growth retardation and oligohydramnios by two dimensional Doppler ultrasonography].
Renal blood flow dynamics were studied with color and pulsed Doppler ultrasound in 102 normal fetuses at 20 to 40 weeks of gestation, 11 growth retarded fetuses (group A), 15 fetuses with oligohydramnios (group B) and 10 growth retarded and oligohydramniotic fetuses (group C) at 32-40 weeks of gestation. The maximum systolic velocity (VMAX), early diastolic peak velocity (VEA), end diastolic velocity (VED) and resistance index (RIEA:VMAX-VEA/VMAX and RIED:VMAX-VED/VMAX) were measured in the renal artery. VMAX was also measured in the ascending aorta (AO) and pulmonary artery (PA). In the normal fetuses, blood flow velocity increased with gestational age, but VMAX and VEA remained constant after 28 weeks of gestation. The resistance index decreased with gestational age, but RIEA remained constant after 28 weeks of gestation. RIED in groups A and C increased significantly, and VMAX in groups B and C, and VED in group C decreased significantly compared with normal fetuses. VMAX in AO and PA decreased remarkably in the three abnormal groups. It was concluded that the kidneys were poorly perfused in the growth retarded fetuses with oligohydramnios, which may, in part, depend on the decreased stroke volume.