Evaluation of Fetal Renal Artery Doppler Indices in Pregnancies Complicated with Preeclampsia

Abstract

Objective: Preeclampsia, characterized by endothelial dysfunction, is associated with maternal and fetal Doppler alterations. This study aimed to evaluate fetal renal artery Doppler indices in pregnancies complicated with preeclampsia and compare them with normotensive pregnancies. Design: This cross-sectional study enrolled 46 pregnancies complicated with preeclampsia between weeks 24 and 37 of gestation as the study group and 48 normotensive pregnancies as the control group. Materials and Methods: The abdominal aorta, its bifurcation, and the renal arteries were visualized in the coronal view of the fetal abdomen using color Doppler. Renal artery Doppler indices were measured after arising from the abdominal aorta. The angle of insonation was ≤30° from the direction of blood flow, and the sample volume was 2 mm. Fetal renal artery pulsatility index, resistance index, systolic/diastolic ratio, and peak systolic velocity (PSV) were measured. All Doppler measurements were performed in the absence of fetal movements. Moreover, demographic characteristics and the perinatal outcome data of patients were recorded. Results: The values of fetal renal artery pulsatility and resistance indices were found to be significantly lower in the study group than those in the control group (p < 0.001 and p = 0.013, respectively). The fetal renal artery systolic/diastolic ratio and PSV values were also significantly lower in the study group compared with those in the control group (p = 0.007 and p < 0.001, respectively). Renal artery pulsatility and resistance indices were negatively correlated with mean arterial pressure (r = −0.381, p < 0.001 and r = −0.267, p = 0.009, respectively). The renal artery systolic/diastolic ratio was also significantly negatively correlated with the mean arterial pressure (r = −0.257, p = 0.013). Limitations: The main limitations of this study are its cross-sectional design and the small number of participants. Another limitation of the study is that preeclamptic pregnancies complicated with fetal growth restriction were not included. Conclusion: The observed decrease in fetal renal artery Doppler impedance may be caused by the unique response of the fetal renal artery to the factors involved in the etiopathogenesis of preeclampsia than other fetal peripheral vessels. These changes in fetal renal artery indices in pregnancies complicated with preeclampsia could be taken into account in the assessment of fetal health.