Longitudinal study of the newborn small for gestational age. Growth recovery and conditioning factors

Background: small-for-gestational-age (SGA) newborns present a higher morbidity and mortality rate when compared to infants born appropriate for gestational age (AGA), as well as insufficient growth, with height far from their target and in some cases a low final height (< -2 SDs). Objective: the aim of this study was to determine when catch-up growth (CUG) in height occurs in these children, and which factors are associated with lack of CUG. Material and methods: this is a retrospective study of SGAs born between 2011 and 2015 in a secondary hospital. Anthropometric measurements were taken consecutively until CUG was reached, and fetal, placental, parental, newborn, and postnatal variables were studied. Results: a total of 358 SGAs were included from a total of 5,585 live newborns. At 6 and 48 months of life, 93.6 % and 96.4 % of SGAs achieved CUG, respectively. By subgroups, symmetric SGAs performed worse than asymmetric SGAs with CUG in 84 % and 92 % at 6 and 48 months of life, respectively. The same occurred in the subgroup of preterm SGAs with respect to term SGAs, with worse CUGs of 88.2 % and 91.2 % at 6 and 48 months of life, respectively. Prematurity, symmetrical SGA, intrauterine growth retardation (IUGR), preeclampsia, previous child SGA, perinatal morbidity, and comorbidity during follow-up were associated with absence of CUG. Conclusions: the majority of SGAs had CUG in the first months of life. The worst outcomes were for preterm and symmetric SGAs.