How Fast Should the Preterm Infant Grow?

It is clear that the gold standard for weight gain in the preterm infant is to achieve the rate gain of the fetus at the same postconceptional age. This goal is not always easy to achieve, though at the time of discharge most preterm infants are at least growing parallel to the appropriate intrauterine growth curve. Current guidelines for dietary intake do not allow for the necessary “catch-up” growth after the inadequate nutrition of the early weeks of life. Assessment of growth in the neonatal intensive care unit (NICU) should include accurate measurements of weight, length and head circumference. Growth velocity should also be calculated. Anthropometric measurements should be assessed using one of the presently available newer intrauterine growth curves. Postnatal curves showing how preterm infants actually grow are also available and allow for comparison of one preterm infant’s growth with other preterm infants. These are particularly useful in the early weeks of life before the infant regains the birth weight and achieves a steady upward growth velocity. The need for catch-up growth is a challenge given the concerns about metabolic programing and adverse outcomes of rapid growth, especially in the preterm infant who is small for gestational age. It is also clear that adequate head growth is very important for neurodevelomental outcome. This article ends with a suggested individualized practical growth strategy for preterm infants in the NICU.