FETAL RENAL-ARTERY AND UMBILICAL ARTERY DOPPLER FLOW AND FETAL URINE OUTPUT

The object of this study was to determine if a correlation exists betw een the resistance index (RI) of the umbilical artery, the RI of the f etal renal artery, and hourly urine output by fetuses of normal pregna ncies. Doppler flow study of the fetal renal artery and the umbilical artery was performed in 110 fetuses between 19 and 40 weeks' gestation . Color and pulse wave Doppler was used to obtain the flow velocity wa veforms. The RI of the flow velocity waveforms was calculated. Fetal b ladder volume was calculated by transverse, anteroposterior, and longi tudinal diameters obtained from coronal and transverse sonographic ima ges of the fetal urinary bladder. The difference in bladder volume at 30-minute intervals was used to determine hourly urine output. Gestati onal age has a positive linear association with fetal urine output (P <0.01). The RI of the fetal renal artery has a negative linear associa tion with gestational age (P <0.05). The RI of the umbilical artery de creased with an increase in gestation age (P <0.01). There was a signi ficant correlation between the RI of the umbilical artery (P <0.01) an d the fetal renal artery (P <0.05) and hourly urine output by the fetu s. The RI of the fetal renal artery decreased with gestational age. Ho urly urine output of the fetus increased with gestational age. The RI of the umbilical artery and the fetal renal artery had a significant c orrelation with fetal urine output.