The effects of gestational age and growth restriction on compensatory kidney growth

Low birth weight is associated with altered renal development, adult onset hypertension and renal disease. The aim of this prospective longitudinal study was to estimate the renal growth during the first 2 years of life in small-for-gestational age (SGA) infants of varied gestational age (GA) and with differing degrees of growth retardation (GR) at birth. Material and methods. The study included 466 children: SGA, n = 243, and appropriate-for-gestational age (AGA), n = 223, classified according to GA into three groups (28-34, 34-36 and >36 weeks, respectively). The SGA children were also classified according to the degree of GR: birth weight <3rd percentile, and birth weight 3-10th percentiles. Serial renal ultrasonography (US) for kidney length (KL) measurement was performed at the ages of 36 and 40 weeks corrected age and 3, 6, 12 and 24 months of chronological age. The ratios of KL(3) to crown to heel length (CHL), body weight (BW) and body surface area (BSA) were used as estimators of relative kidney length (RKL).