Fetal Renal Artery Doppler in Cases of Isolated Oligohydramnios: Can it Predict Adverse Neonatal Outcome?

Abstract

Aims and Objectives: This study compares the fetal renal artery flow velocity waveforms of pregnancies complicated by oligohydramnios with normal pregnancies and to detect any statistically significant difference between the two Groups and to further determine the relationship of these findings with neonatal outcome. Method: All pregnant women in IIIrd trimester with gestational age between 32 weeks to 36 weeks with isolated oligohydramnios were included as cases (Group-A). Normal IIIrd trimester pregnancies (Group-B) with gestational age between 32 weeks to 36 weeks served as controls between the study period of Jan 2018 to Dec 2019. Results: The mean umbilical artery pulsatility index (PI; mean ± SD) in patients of Group-A was 1.0730 ± 0.0637 and that of patients in Group-B was 1.0012 ± 0.1400 with P = 0.0023. The mean umbilical artery S/D ratio (mean ± SD) in patients of Group-A, was 2.9120 ± 0.2476 and that of patients in Group-B was 2.5135 ± 0.2751 with P < 0.0001. The mean renal artery PI (mean ± SD) in patients of Group-A was 2.5863 ± 0.2608 and that of patients in Group-B was 2.4737 ± 0.2648 with P = 0.0240. The mean birth weight and Apgar Score were also found to be statistically significant between the two Groups. Conclusion: The distribution of mean renal artery PI and umbilical artery PI, in oligohydramnios cases, was higher in comparison to normal cases. As the Neonatal intensive care unit (NICU) admission was higher in the oligohydramnios group with abnormal renal artery doppler indices, our recommendation is that abnormal fetal renal artery Doppler indices are an indication for early referral to tertiary care setup, as the majority of these neonates will require NICU care postdelivery.