Body Composition following Necrotising Enterocolitis in Preterm Infants

The optimal nutritional regimen for preterm infants, including those that develop necrotising enterocolitis (NEC), is unknown.

The objective here was to evaluate body composition at term in infants following NEC, in comparison with healthy infants. The primary outcome measure was non-adipose tissue mass (non-ATM).

We compared body composition assessed by magnetic resonance imaging at term in infants born <31 weeks of gestational age that participated in NEON, a trial comparing incremental versus immediate delivery of parenteral amino acids on non-ATM, and SMOF versus intralipid on intrahepatocellular lipid content. There were no differences in the primary outcomes. We compared infants that received surgery for NEC (NEC-surgical), infants with medically managed NEC (NEC-medical), and infants without NEC (reference).

A total of 133 infants were included (8 NEC-surgical; 15 NEC-medical; 110 reference). In comparison with the reference group, infants in the NEC-surgical and NEC-medical groups were significantly lighter [adjusted mean difference (95% CI) NEC-surgical: -630 g (-1,010, -210), p = 0.003; NEC-medical: -440 g (-760, -110), p = 0.009] and the total adipose tissue volume (ATV) was significantly lower [NEC-surgical: -360 cm3 (-516, -204), p < 0.001; NEC-medical: -127 cm3 (-251, -4); p = 0.043]. There were no significant differences in non-ATM [adjusted mean difference (95% CI) NEC-surgical: -46 g (-281, 189), p = 0.70; NEC-medical: -122 g (-308, 63), p = 0.20].

The lower weight at term in preterm infants following surgically and medically managed NEC, in comparison to preterm infants that did not develop the disease, was secondary to a reduction in ATV. This suggests that the nutritional regimen received was adequate to preserve non-ATM but not to support the normal third-trimester deposition of adipose tissue in preterm infants.