ABSTRACT
Objective:To evaluate the changes of fetal renal artery blood flow parameters in fetuses with isolated borderline oligohydramnios (IBO) in the middle and third trimesters by Doppler ultrasound, and to assess its correlations with maternal and infant pregnancy outcomes.Methods:Twenty-seven IBO fetuses (IBO group) and 27 gestational age-matched normal fetuses (control group) from April to October 2019 in the Second Xiangya Hospital of Central South University underwent prenatal ultrasound examination during the middle and third trimesters. Renal artery blood flow parameters, including renal artery pulsatility index (RAPI), volume corrected renal artery pulsatility index (vcRAPI) and pregnancy outcomes were measured and compared between the two groups. Once diagnosed IBO, patients were recommended to the obstetric clinic for consultation and intervention. The correlation between RAPI, vcRAPI measured before intervention and prepartum amniotic fluid volume and pregnancy outcomes was analyzed, the ROC curve was plotted to find the better predictor.Results:The vcRAPI of the IBO group was higher than that of the control group ( P=0.015). In the IBO group, the vcRAPI measured before intervention was higer in those fetuses who were still IBO before delivery( P=0.048). In the IBO group, the correlation of the vcRAPI measured before intervention and IBO before delivery was statistically significant ( OR=2.41, 95% CI=1.06-5.43, P=0.035). The ROC curve showed that the sensitivity of vcRAPI to IBO was 0.67, the specificity was 0.75( P=0.002). Conclusions:Compared with RAPI, The vcRAPI may reflect the increase in fetal renal artery perfusion resistance of IBO group more timely. The higher vcRAPI before intervention in the IBO group have difficulty in recovering amniotic fluid volume before delivery.Increased vcRAPI is a better predictor of IBO before delivery.