Fetal Renal Artery Indices of Second and Third Trimesters of Pregnancy in Idiopathic Oligohydrominos by Pulsed Wave Doppler Ultrasonography

Background: Amniotic fluid volume is an indicator of fetal well-being in second and third trimesters of pregnancy and oligohydramnios is diagnosed when this volume is less than 500 ml. Flow velocity waveforms of the renal arteries by doppler ultrasonography provide a sensitive method to predict changes in amniotic fluid dynamics and index in early stages of pregnancy. Aim: To determine the relation of renal artery flow velocity waveforms with normal pregnancies and with pregnancies complicated by oligohydraminos using doppler ultrasonography. Methods: A doppler ultrasound device was used to assess the renal artery pulsatility index (PI), resistance index (RI), systolic/ diastolic (S/D) ratio. 3 consecutive waveforms from each fetus were traced and the average values used for final analysis. Results: Maternal age ranged from (20 -40) years. Fetal age ranged from (21 -38) weeks. In oligohydramnios cases, median of (PI) in Lt kidney was (1.99) and in Rt kidney was (2.14), while median of (RI) in Lt kidney was (0.8372) and in Rt kidney was (0.852). While in normal cases median of (PI) in Lt kidney was (1.4584) and in Rt kidney was (1.4124), while median of (RI) in Lt kidney was (0.71) and in Rt kidney was (0.69988). Conclusion: There is a relation between renal arteries flow velocity waveforms and oligohydraminos by using doppler Ultrasonography. Oligohydramnios with markedly changes in PI & RI values especially in the third trimester is an indicator for rapid delivery to save fetal life. Oligohydramnios could be predicted according to changes in PI & RI values.