441 - Longitudinal Changes of Macronutrients in Preterm Milk Through 40 Weeks Corrected Gestational Age (CGA)

Poster Number: 441
Publication Number: 441.334

Deena E. Merzel, Maria Fareri Children's Hospital at Westchester Medical Center, Flushing, NY, United States; Jordana Gross, New York Medical College, Jamaica, NY, United States; Tina Roeder, Westchester Medical Center, Piermont, NY, United States; Clare Giblin, Maria Fareri Children's Hospital at Westchester Medical Center, Valhalla, NY, United States; Boriana Parvez, Maria Fareri Children's Hospital at Westchester Medical Center, Valhalla, NY, United States

Background: Human breastmilk is fortified to provide complete nutrition for preterm infants. Most commonly, fortification adds a set amount of a standardized fortifier to the human milk to achieve a specified caloric and macronutrient content. Less commonly, individualized fortification adjusts fortification based on the infant’s metabolic response or the measurement of the macronutrients using a human milk analyzer. There is a paucity of data on the longitudinal changes in macronutrient content of preterm breastmilk.

Objective: To identify patterns of gestational age specific macronutrient content that will guide individualized fortification.

Design/Methods: This IRB study enrolled mothers of neonates less than 37 weeks gestation admitted to Maria Fareri Children’s Hospital. Expressed breastmilk samples were collected weekly from birth until 40 weeks corrected gestational age (CGA). Analysis of milk samples was performed using an FDA-approved human milk analyzer measuring fat, protein, carbohydrate and energy content using near-infrared spectroscopy.

Results: When analyzing by CGA, protein content ranged from 1.5g/100ml to 0.7g/100ml at a CGA of 24 and 40 weeks respectively. There was a protein and caloric content of 1.2 ± 0.4 g/100ml and 20.5 ± 4 cal/oz prior to 35 weeks, and a protein and caloric content of 1.0 ± 0.4 g/100ml and 20.8 ± 4.5 cal/oz after 35 weeks (mean ± standard deviation) (Table 1). The starting protein content of the breastmilk differs based on gestational age, thus protein content during the same CGA varies (Graph 1). Longitudinally, there is a decrease in protein content over time, a relatively stable carbohydrate level, and variable fat and energy levels (Graphs 1 and 2).Conclusion(s): Maternal contribution towards the macronutrient content of breastmilk accounts for variability within samples of the same CGA. The earlier preterm the delivery, the higher the protein content at birth. Based on a 150ml/kg diet, preterm breastmilk alone is not meeting the recommended protein intake of 4g/kg/day nor the recommended caloric intake of 120kcal/kg/day. Individualized fortification with predominant protein fortification based on gestational age should be used considering the steady decrease in protein content. Further, calories can be provided with a high-fat maternal diet and utilization of hindmilk, accounting for variability both within a single mother as well as between mothers.
Table 1: Macronutrient Content in Preterm Milk Through 40 Weeks Gestational AgeSamples of preterm breastmilk from 23 weeks gestational age through 40 weeks corrected gestational age. The protein, fat, carbohydrate, and energy content are represented by mean and standard deviation.
Graph 1: Protein content of preterm breastmilkLongitudinal changes of protein content in preterm breastmilk, measured in grams per 100 milliliters, as represented by three individual mothers; the first mother delivered at 23 weeks gestation, the second delivered at 26 weeks gestation, and the third delivered at 30 weeks gestation.