Background: Small-for-gestational-age (SGA) neonates are at a higher risk of adult-onset metabolic disorders because of fetal programming in the presence of growth restriction. Nephrogenesis may also be affected in fetal growth restriction. This study hypothesized that urinary podocalyxin levels, a marker of nephrogenesis, would be lower among preterm SGA neonates as compared to appropriate-for-gestational-age (AGA) controls.
Methods: This cross-sectional study enrolled gestation-matched SGA (n = 90) and AGA (n = 45) neonates born at 260-366 weeks of gestation. The SGA group comprised of 45 neonates with birth weight between 3rd and 10th centile and 45 neonates with birth weight <3rd centile. The primary outcome of the study was the difference in urinary podocalyxin levels between SGA and AGA neonates. Glomerular and tubular functions were also assessed.
Results: Urinary podocalyxin levels were similar in SGA and AGA neonates (ng/mg of creatinine; median [interquartile range]: 28.7 [4.8-70.2] vs. 18.7 [3.1-55.9]), P value 0.14). No correlation was observed between birth weight centile and urinary podocalyxin levels (r: -0.06). Glomerular filtration rate, fractional excretion of sodium, and serum β-2-microglobulin levels were comparable across the study groups.
Conclusions: Glomerular development as assessed by urinary podocalyxin levels and renal functions are comparable in SGA and AGA preterm neonates.
Impact: Neonates born with fetal growth restriction are at a higher risk of adult-onset metabolic disorders because of fetal programming. This cross-sectional study investigated the effect of presence and severity of fetal growth restriction on glomerular development by measuring urinary podocalyxin levels in preterm infants. This study did not observe any effect of the presence or severity of fetal growth restriction on urinary podocalyxin levels and other markers of glomerular and renal tubular functions.