Preterm infants are vulnerable to the effects of malnutrition in both the pre- and post-discharge period. On-going illness and immaturity result in a delay in the establishment of adequate nutrition. During this period, cumulative nutrient deficits are accrued and growth is poor. The majority of preterm infants are discharged with a weight lower than their birth centile, indicative of poor growth. Nutrition has the potential to promote catch-up growth, although growth acceleration in some situations is associated with increased risk of metabolic problems in the longer term. Controlled trial data show that early nutrient intakes may ‘programme’ a range of long term metabolic outcomes. The Developmental Origins of Health and Disease (DOHaD) theory amalgamates many areas of scientific study and encompasses a wide range of diverse disciplines from epidemiology to molecular biology. The mechanisms linking early growth to later outcomes include permanent structural changes, accelerated cellular ageing and epigenetic mechanisms. There are data to link faster early growth with decreased insulin sensitivity in children born preterm, but many other long-term effects do not demonstrate consistent associations with early growth. Despite such potential metabolic concerns, the current data suggest that promoting improved nutrient intake and catch up growth in the pre- and post-discharge period is likely to result in better neurocognitive outcomes.
