The goal of current nutritional recommendations is to support a growth pattern that mimics physiologic fetal growth. Are we routinely meeting that goal? Probably not, as the premature and especially the ELBW infant grows more slowly after birth if we compare them to the growth rates of normal fetuses. Certainly neonatal morbidities and inherent differences that exist between the intrauterine and the postnatal environment and metabolic conditions make this goal to mimic the fetus challenging.

One major problem that confronts all of these infants and is fundamental to growth is their nutrient intakes. This intake is often less than the support necessary to mimic fetal growth. The Lucas data relating nutrient content (protein and energy) of formula with mental and motor outcomes later in life and the NICHD Growth Observation Study linking in-hospital growth velocity with cognition, neurologic impairment, and growth outcomes at 18–22 months of age clearly demonstrate why avoidance of growth restriction is so important.

Nutrient intakes currently recommended by various international committees and expert panels are discussed in this book and are based on the concept of providing sufficient nutrients to achieve postnatal growth approximating that of a normal fetus of the same postmenstrual age. Nutritional requirements do not stop at birth. After birth, the newborn infant starts using its own glycogen and fat reserves and its protein in muscle and other organs and tissues, to maintain metabolic rate. Waiting “until the infant is stable” is incorrect because without early TPN these ELBW infants enter a catabolic condition and rapidly exhaust energy reserves.