Feeding very low birth weight infants after discharge, especially those receiving breast milk, is a challenge made harder by the prevalence of infants who are small for their age. More needs to be done in neonatal intensive care units to help ensure that these infants grow better before being discharged home.

In this issue, O'Connor et al tackle the important and difficult issues surrounding the nutritional support of very low birth weight (VLBW) infants who receive breast milk and are cared for outside of the highly specialized neonatal intensive care unit (NICU) setting. Their concern about the lack of research and guidelines for the nutritional care of VLBW infants after discharge is entirely appropriate and is shared by other clinicians caring for these infants.

However, there is more to the story. As the authors indicate, many VLBW infants grow poorly and are not optimally nourished by the time they are discharged from the NICU. Several large multicenter studies have documented high rates of neonatal growth faltering in premature infants in NICUs. 1,2 In particular, Lemons et al reported that although the rate of small-for-gestational age (<10th percentile weight-for-gestational age) infants was approximately 20% in their VLBW infants at birth, 97% were <10th percentile weight-for-corrected gestational age by the time they were 36 weeks old. 2 This neonatal growth restriction is a significant complication among VLBW infants in the NICU. Furthermore, even among infants of the same birth weight, growth varies from one NICU to another. 1,3 Therefore, practices that improve the growth of VLBW infants while they are still in the NICU must be identified and acted on to lessen nutritional deficits at the time of discharge and make it easier for these infants to grow better as outpatients.

Growth of premature infants in NICUs depends on many nonmodifiable factors, including size, gestational age, and general health at admission. However, the other practices that affect their growth are ones on which we can act. 3,4 These include early and intensive nutrition to help support elevated needs 5; minimal use of postnatal corticosteroids, a catabolic steroid known to impede short-term growth 6; and potentially the early and extended use of incubators to help minimize energy expended to maintain body temperature. 7 The NICU healthcare team may also help to improve the growth status of VLBW infants by lessening their initial weight loss. Within the first week of life, all infants, especially very premature infants, lose weight. Typically, they reach a nadir that is 10%-20% below birth weight. However, the further infants fall below their birth weight early in the neonatal period, the more likely they are to be discharged <10th percentile weight-for-corrected gestational age, even if their growth rates in the NICU reach the goal of intrauterine growth levels. Although some weight loss within the first days of life is appropriate, excessive weight loss after birth must be avoided. Some VLBW infants with complicated health problems may grow poorly, despite attentive and intensive care, yet further optimization of the care provided in the NICU may help to minimize the neonatal growth restriction.

The benefits of early and intensive nutrition on the growth and development of VLBW infants are clear. 5 Nutrition, particularly protein intake, is a strong predictor of growth during the neonatal period. 3 Current recommendations for VLBW infants are for the initiation of parenteral protein within the first 24 hours of life at levels ranging from 1 to 3 g/kg/day and 4 g/kg/day for enteral feedings. 5 Consistent use of these expert recommendations has the potential to blunt the degree of initial weight loss and catabolism of protein stores, support later growth velocity, and thus, improve growth status of VLBW infants in the NICU. Despite the documented benefits, these practices have not yet been adopted by many US NICUs.

Numerous enteral products are used to feed VLBW infants in the NICU. Human milk is the feeding of choice for all VLBW infants. However, human milk requires additional calories, protein, vitamins, and minerals to adequately support the rapid growth and development of these tiny infants. Special human milk fortifiers, preterm infant formulas, and modular supplements (eg, carbohydrate, fat, and protein-predominant products) are available to supplement breast milk and are routinely used within hospitals. When preterm formulas are used in place of or in conjunction with fortified breast milk in VLBW infants, formula and/or modular supplements are also used to increase nutrient content. Use of these concentrated feedings of fortified breast milk and/or preterm formula in the NICU setting, coupled with close monitoring of each infant's tolerance, permits the healthcare team to optimize intakes and wean the infants to other feeds as their growth improves.

Hospital lengths of stay are becoming shorter, and infants are being sent home from NICUs younger and smaller than ever before. Therefore, more attention must be focused on how to provide less intensive but carefully monitored nutritional care in outpatient settings. The O'Connor article calls attention to the need for such guidance. It describes the paucity of postdischarge dietary recommendations for VLBW infants. There are several studies on the nutritional and growth benefits of using "nutrient-enriched" or "postdischarge" formulas after discharge in VLBW infants. Yet little research has been done on the adequacy, safety, and efficacy of various alternatives for meeting the increased nutritional needs of VLBW infants fed breast milk. Although human milk remains the feeding of choice for VLBW infants after discharge, the products to fortify it are often expensive and not regularly stocked in US retail stores. There is also the danger of overnutrition, particularly of fat-soluble vitamins, when the fortifiers are used outside of the closely monitored NICU setting. Full-term and postdischarge formulas are used to supplement breast milk with additional nutrients after discharge, but these feedings provide much less nutrition per volume than the products used in NICUs, suggesting risks of undernutrition. Currently, there is no consensus on how to solve these obstacles to meet the elevated nutritional needs of the VLBW infants after hospital discharge.

Variations in the availability of specific types of formulas and nutritional follow-up for VLBW infants after discharge may create different challenges for the healthcare professionals in the United States and Canada. However, it is clear that we need more studies on the nutritional needs of VLBW infants after discharge from the NICU and on safe and efficacious methods to achieve the elevated needs of these infants. O'Connor et al are to be commended for starting to document the gaps in these important areas of premature infant care, but much remains to be done. In the meantime, further efforts are needed in the nutritional management of VLBW infants in the NICU to improve their growth and nutritional status before discharge.

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