Third Trimester Fetal Renal Artery Doppler Indices in Borderline Idiopathic Isolated Oligohydramnios and Relationship Between Neonatal Outcomes

During a routine pregnancy examination at 34-37 weeks gestation, the fetus was evaluated using ultrasound with the Toshiba Xario 200 3.5-megahertz probe. Fetal biometric measurements were obtained and placental structure and the amniotic fluid amount were evaluated in four quadrants. After detailed ultrasonography of the fetus, eligible pregnant women were included in the study.

Borderline idiopathic isolated oligohydramnios was defined according to the four quadrants technical with ultrasound examination and diagnosed with amniotic fluid index >5.0 and ≤8.0cm. After first ultrasound examination all patients in borderline isolated oligohydramnios group were hydrated with one to two liters of water daily. All patients monitored with non stress test and amniotic fluid index twice weekly until delivery after treatment with hydration.

For evaluating renal artery blood flow, an axial image of the fetal abdomen was obtained at the level of the fetal kidneys. Using color flow Doppler, the renal arteries were evaluated at the level of their origin from the abdominal aorta. The Doppler gate was placed within the lumen in a straight segment of the vessel. A minimum of three consecutive waveforms was used to calculate the PI. The umbilical artery Doppler measurements were studied in a free loop of cord, far from the fetus and placenta. pulsatile index and resistance index values were recorded.

The study consisted of two groups. The first group was formed of the patients who had normal amniotic volume and meets the inclusion criteria. In second group the investigators included patients who diagnosed borderline idiopathic isolated oligohydramnios. After delivery the investigators compared fetal renal artery doppler indices and neonatal outcomes between groups.