The neonatologist's dilemma: catch-up growth or beneficial undernutrition in very low birth weight infants-what are optimal growth rates?

As the threshold of viability decreases, clinicians who care for preterm neonates increasingly are faced with making decisions regarding feeding in a population for which there are no clear guidelines and minimal scientific data to inform optimal nutritional strategies. It is becoming more apparent that the amount of nutrition, as well as the timing of nutrient delivery, may affect long-term growth and metabolic outcomes. Both overnutrition and undernutrition at critical growth periods may have adverse effects. The risks and benefits of nutrient delivery designed to achieve "catch-up" growth need to be further identified. This article reviews both established concepts and more recently identified issues that need to be considered by the neonatologist when making feeding decisions in the very preterm neonate.