Performance of Fetal Renal Artery Doppler Compared with Umbilical Artery Doppler in Mild and Moderate Fetal Growth Restriction: An Observational Study in a Tertiary Care Hospital

Ab s t r Ac t Background: Fetal growth restriction (FGR) and oligoamnios are one of the major reasons of preterm delivery and low birth weight contributing to almost two-third of neonatal mortality. Fetal kidney, in addition to placenta, acts in controlling and regulating physiology of the fetus. Doppler ultrasound has become a part of routine antenatal care in monitoring such high-risk pregnancies. However, renal artery was the least studied. Aim and objective: To compare the relationship of perinatal outcomes with renal artery Doppler and umbilical artery Doppler indices. Materials and methods: A prospective observational study carried out among women attending an antenatal clinic and who have undergone delivery in Department of Obstetrics and Gynecology, in a tertiary care hospital between August 2016 and May 2018. Regular ultrasonography was done at 28–31 weeks; they were followed up 4 weeks later and Doppler indices were noted. Results: In the 394 patients studied, 13.1% were having FGR, 12.2% were oligoamnios, and 12.2% had preterm delivery. The p values of the pulsatility index and the resistivity index of the renal artery in FGR, oligoamnios, preterm delivery, and low birth weight were more significant than umbilical artery Doppler indices. Conclusion: Renal artery Doppler indices were significantly more reliable in predicting adverse perinatal outcomes in cases of mild uteroplacental insufficiency. Additionally, renal artery Doppler indices were able to pick up these changes earlier than umbilical artery Doppler, hence a potential early indicator, and the pulsatility index being more specific and sensitive. Limitations: Sample size of the study is limited with only mild cases of FGR. Larger studies are required. In addition, patients at a higher risk of FGR in comparison with low-risk cases should be studied with more sample size as this study did not show any significant association with comorbidities.