Prediction of the outcome of growth at 2 years of age in neonates with intra-uterine growth retardation

Abstract

The aim of the study was to identify at birth, in infants showing intra-uterine growth retardation (IUGR), any parameters correlative with the increase in height SDS during the first 2 years of life and with short stature at 2 years of age, and to determine whether the sensitivity and specificity of such parameters would permit their use as predictors of short stature at 2 years of age. Two cohorts of children born with IUGR with birth weight < 3rd percentile, were studied. In the first group of 317 children selected at birth, 224 were effectively followed up to 2 years of age (group 1) and the second group of 48 children was evaluated at 2 years of age for short stature related to IUGR (group 2). Perinatal history, auxological data at birth and parental height were monitored in a prospective study for the group 1 children and in a retrospective study for the group 2 children. By 2 years of age, 8% of the 224 children followed (group 1), presented short stature (< or = 2 SDS). In a multiple linear regression model, gestational age, birth length (SDS), target height (SDS) and maternal tobacco consumption were found to be the strongest predictors of the magnitude of the height gain (SDS) during the first 2 years of life. Using these parameters 47% of the variability of the height gain (SDS) during the first 2 years of life could be explained at birth. Moreover, logistic regression analysis showed three risk factors at birth for short stature by 2 years of age: reduced gestational age due to premature birth (adjusted odd ratio (O.R.) = 2.10; 95% C.I. = 1.06-4.14), the greater the difference (for each S.D.) between birth length (SDS) and target height (SDS) (O.R. = 1.93; 95% C.I. = 1.40-2.66) and although as a borderline significant factor, maternal tobacco consumption (O.R. = 1.58; C.I. 95% = 0.81-3.07). Non-parametric discriminant analysis was used to investigate whether short (< or = -2 SDS) or normal stature (> -2 SDS) at 2 years could be predicted at birth using gestational age (weeks), birth length (SDS), target height (SDS) and maternal tobacco consumption as discriminant variables. We found that this discriminant model correctly predicted at birth the short stature of 57 of 59 children at 2 years of age (sensitivity 97%) and the normal stature of 142 of 159 children at 2 years of age (specificity 89%). In conclusion, an accurate prediction of short stature by 2 years of age is feasible at birth in the IUGR neonate.