Infants born small for gestational age often show impaired growth during childhood and reduced height as adults. Infants who are breast-fed from birth show greater 'catch-up' growth during the first few months of life than those who are formula fed but it is not clear what factors in breast milk (ie protein, nucleotides, LCPUFAs) are responsible for this 'catch-up' growth. This RCT compares the effects of using an enriched formula with increased protein and modified triglyceride (palmitate predominantly in Sn-2 position) against a standard infant formula from birth to six months on infants whose birth weights are below the 20th centiles for gestational age.