RESUMEN
Beginning and achieving full enteral nutrition is a key step in the care of preterm infants, particularly very low birth weight (VLBW) infants. As is true for many organ system-specific complications of prematurity, the gastrointestinal tract must complete in utero development ex utero while concurrently serving a physiologic role reserved for after completion of full term development. The preterm gut must assume the placental function of the interface between a source of energy, precursors for anabolism, and micronutrients, and the developing infant-through digestion and absorption of milk, instead of directly from the mother via the uteroplacental interface. The benefits of enteral nourishment in preterm infants are counterbalanced by gastrointestinal complications of prematurity: dysmotility leading to difficulty establishing and advancing feeds, and the risk of necrotizing enterocolitis (NEC). Concern for these complications can prolong the need for parenteral nutrition with an associated increase in risk for central line-associated bloodstream infection (CLABSI) and parenteral nutrition (PN)-associated cholestasis or liver disease (PNALD). Thus, a daily issue facing neonatologists caring for preterm infants is how to optimally begin, advance, and reach full enteral nutrition sufficient to satisfy the nutrient, energy, and fluid requirements of VLBW infants while minimizing risk. In this perspective, we provide an overview of the approaches and supporting data for starting and advancing enteral feeds in preterm infants, particularly very low birth weight infants, and we discuss the significant gaps in knowledge that accompany current approaches. This framework recognizes the dilemmas of preterm feeding initiation and advancement and identifies areas of opportunity for further investigation.