Projects

Background: To assess the renal growth and function of neonates during infancy in relation to birth weight and
gestational age.
Methods: A longitudinal study was conducted at a tertiary hospital in South India from June 2010 to August 2014.
Low birth weight neonates (LBW) were further sub-classified based on gestational age and compared with normal
birth weight (NBW) full term neonates at birth, 6 months and 18-24months of age. The renal volume was measured
by ultrasound and renal function by Cystatin C- derived glomerular filtration rate (CysGFR) at the three time points
during the dynamic phase of renal maturation in infancy.
Results: We recruited 100 LBW and 66 NBW term neonates. Thirty five percent of the LBW neonates were SGA.
Among the AGA neonates, 39 % were LBW neonates. The mean height and weight of the LBW neonates were
significantly lower compared to NBW neonates throughout infancy. The increment in kidney volume was in
accordance with the change in body size, being lower in LBW compared to NBW infants. The combined kidney
volume was significantly lower in LBW and SGA neonates across all three time points (p < 0.001). CysGFR in the
LBW and SGA infants, despite having low kidney volumes, were comparable to the GFRs of NBW and AGA
neonates at the end of infancy.
Conclusion: This study highlights the fact that both birth weight and gestational age influence kidney growth and
function in infancy. At the end of infancy, despite a significant difference in kidney volumes and age at last follow
up, the glomerular filtration rate was comparable between LBW and NBW infants. Though not statistically
significant, there was a trend towards higher urine microalbumin in LBW compared to NBW in infancy.