Nutritional Practices and Growth Velocity in the First Month of Life in Extremely Premature Infants

Abstract

OBJECTIVES The goals of this study were to describe nutritional practices in the first month of life for a large cohort of extremely low gestational age newborns and to determine the impact of these nutritional practices on growth velocity over the same period. METHODS The sample included 1187 infants born at 23 weeks to 27 weeks of gestation, at 14 institutions, between 2002 and 2004. Inclusion criteria included survival until day 28 and weight information for both day 7 and day 28. Growth velocity, expressed as grams per kilogram per day (g/kg/day), was calculated for the interval between days 7 and 28. Nutritional practices during the first week and on days 14, 21, and 28 were compared to current nutritional guidelines in the literature. Multivariable logistic regression models estimated the contribution of limited nutrition to limited growth velocity. RESULTS Protein and fat delivery approximated current nutritional recommendations while carbohydrate and total caloric delivery did not. Despite this, growth velocity of our study infants exceeded the current guideline of 15 g/kg/day. Nevertheless, we found extrauterine growth restriction (i.e., weight for gestational age below the 10th centile) in 75% of infants at 28 days, as compared to only 18% at birth. A growth velocity of 20-30 g/kg/day was associated with infants' maintaining or exceeding their birth weight Z-score, with rates in the upper range for the gestationally youngest infants. Early (day 7) nutritional practices were positively associated with growth velocity measured between days 7 and 28. CONCLUSION The early provision of nutrients is an important determinant of postnatal growth. Extrauterine growth restriction remains high in extremely premature infants even when they achieve a growth velocity rate within current guidelines.

Outcomes of early parenteral nutrition for premature infants

“…31 Despite this, 75% of the infants had extrauterine growth restriction at day 28 of life. In our study, we did not find a difference in overall growth velocity in the two periods.…”

Evaluation of human milk fortification from the time of the first feeding: effects on infants of less than 31 weeks gestational age

“…4 Early provision of adequate nutrition for preterm infants can help address their nutritional deficits, and improve growth and neurodevelopmental outcomes; [5][6][7] therefore, the importance of timeliness in meeting these nutritional needs cannot be ignored. One strategy to meet the preterm infant's nutritional needs is fortification of human milk.…”

Generating expected growth curves and Z-scores for premature infants

“…[51][52][53][54][55][56] The Z-score is a dimensionless quantity generated by subtracting a Generating expected growth curves WR Riddle and SC DonLevy population mean (m) from the raw value (x), then dividing by the population standard deviation (s).…”

“…For a normally distributed variable, the 50th percentile is equal to m, the 10th percentile is equal to mÀ1.282s, and the 90th percentile is equal to m þ 1.282s. Bose et al 51 and Martin et al 56 used the 50th percentiles and standard deviations reported by Yudkin et al 46 to generate weight Z-scores for preterm infants. Madden et al 54 used mean and standard deviations reported by Usher and McLean 44 to calculate weight Z-scores for premature infants.…”