Postnatal weight gain in VLBW infants according to intrauterine growth

BACKGROUND: Postnatal growth retardation is a universal problem in VLBW infants. OBJECTIVE: To describe the postnatal weight gain (WG) and weight gain composition (WGC) in a cohort of VLBW infants. DESIGN/METHODS: Prospective observational study. 175 preterm infants were categorized as born AGA without growth retardation (GR) at term (T) (G1:n=45), born AGA with GR at T (G2:n=57), born SGA with GR at T (G3:n=73). Inclusion criteria: BW ≤1500 g, singleton pregnancy, Caucasian parentage. Exclusion criteria: congenital/chromosomal and heart diseases, NEC. Weight and body composition were assessed by an air displacement plethysmography system (PEA POD® Infant Body Composition System, LMI, USA) at T corrected age (c.a.) and 3 months of c.a. In 84 infants weight and body composition were further assessed at 36 wks of c.a. RESULTS: GA (wks) of G3 infants was higher (p<0,001) than that of G1 and G2 infants (31.3, 29.2, 29.5, respectively). Males (%): G1:57; G2:56; G3:48. The mean protein/energy intakes did not differ among groups at any study point.[table1]Table 1: Mean weight (Wt) and fat mass (FM) at birth (B), T c.a., 3 mo c.a. and % delta Wt and FM increase between B and T and between T and 3 mo c.a.[table2]Table 2: Data related to the subgroup of infants. CONCLUSIONS: The WG and the FM increase in G1 infants significantly decrease after T. The WG and the FM increase in G2 and G3 infants show similar trajectory before and after T. Although the FM increase between the 36 wks and T is similar in the 3 groups of infants, the FM at T in G1 infants is higher than that of G2 and G3 infants. At 3 mo ca G3 infants, although presenting a similar trajectory of WG and WGC before and after T, are still lighter than G2 and G3 infants. As intrauterine growth pattern seems to influence the postnatal WG, a strict nutritional follow up of these infants is mandatory