Body composition in preterm infants fed standard term or enriched formula after hospital discharge.

Background: Most preterm infants are still preterm and have a low birth weight when they are discharged from the hospital. An important issue is whether the long-term consequences of early growth restriction can be diminished by nutritional intervention in preterm infants after discharge from the hospital.

Aim: To evaluate differences in growth and in weight gain composition of preterm infants fed standard term formula (SF) or enriched formula (PDF) after discharge from hospital during the first 2 months of life.

Methods: Thirty-three healthy preterm infants, birth weight < 1750 g at gestational age < 35 weeks, were randomised to SF or PDF at the time of discharge from hospital. Anthropometric variables were studied longitudinally and body composition was measured using dual energy x-ray absorptiometry (DEXA) twice, before hospital discharge and two months later. Weight gain composition was calculated as the difference between the two determinations.

Results: Seventeen infants were fed SF and 16 PDF. Anthropometric variables and whole body composition were similar at birth, at the start of the nutritional study (mean age 45 days), and at the end of the study 2 months later. Over the whole study period, weight gain and weight gain composition were similar in the two groups. Sex did not appear to influence weight gain and weight gain composition. In infants with growth restriction at discharge there was a significant reduction of weight gain, fat mass gain, and bone mineral content deposition independently of the formula provided.

Conclusions: There is no immediate effect on preterm infants of a nutrient enriched formula compared with a standard formula on growth, weight gain, or weight gain composition.