649 - Longitudinal Changes of Macronutrients in Preterm Milk Based on Gestational Age at Birth and Corrected Gestational Age

Publication Number: 649.5853

Brianna Cocuzzo, Westchester Medical Center, Dobbs Ferry, NY, United States; Jennifer Kaswick, Maria Fareri Children's Hospital at Westchester Medical Center, New York City, NY, United States; Tina Roeder, Westchester Medical Center, Piermont, NY, United States; Boriana Parvez, Westchester Medical Center, MFCH, BCHP, Valhalla, NY, United States

Background: Breast milk, mother’s own milk or donor milk, is the preferred source of enteral nutrition for premature infants due to the numerous short and long term health benefits, including decreased rates of necrotizing enterocolitis, improved immune function, and improved neurodevelopmental outcomes. However, it has been shown that preterm infants with a breast milk diet gain weight and length more slowly than formula-fed infants. Therefore, human milk is frequently fortified during the first few months of life to help improve their growth. Fortification is often standardized rather than individualized with the assumption that human milk has a static composition approximating the reference term milk with protein 0.9 g/dL, fat 3.5 g/dL, carbohydrates 8.0 g/dL, and calories 66 kcal/dL (20 kcal/oz). Data regarding longitudinal changes of breast milk macronutrients based on gestational age at birth and corrected gestational age (CGA) is limited.

Objective: We aim to identify longitudinal changes in the macronutrient composition of human milk based on gestational age at birth and CGA.

Design/Methods: This IRB approved pilot study examined the breast milk of 22 donor mothers of infants born from 23-35 weeks gestation, who donated milk to the Liquid Gold Preemie Donor Milk Bank at Maria Fareri Children’s Hospital, Westchester Medical Center. Samples were run in 5mL aliquots and analyzed using near-infrared spectroscopy with the MIRIS HMA® – Human Milk Analyzer. The milk samples were assessed for longitudinal changes of the macronutrients (protein, fat, carbohydrates, and calories) by CGA from 23-39 weeks using descriptive statistics.

Results: A total of 79 expressed breast milk samples from 22 mothers of infants born between 23-35 weeks gestation were provided for analysis. Each mother provided an average of 3.6 samples, with mothers of infants born to lower gestational ages providing more samples. The average protein content was 1.4 + 0.3g/dL, average fat content was 3.6 + 1.2g/dL, average carbohydrate content was 7.6 + 0.5g/dL, and average energy content was 72 + 12kcal/dL for all milk samples (Fig 1). Protein content remains elevated above reference term milk over time regardless of GA at birth and CGA (Fig 2).

Conclusion(s): Our results demonstrated that the protein and caloric content remains higher than the reference term milk protein and caloric content through corrected term gestational age of 39 weeks. Our findings support the use of individualized fortification for preterm infants given the longitudinal changes of protein and calories in breast milk based on gestational age at birth and CGA.

Table 1: The Average Macronutrient Content by Corrected Gestational Age
This table demonstrates average caloric content and content of micronutrients protein, carbohydrates, and fat for infants in different gestational age groups.

Longitudinal Changes in Protein Content by Gestational Age at Birth and Corrected Gestational Age
This table demonstrates the average protein composition of the breastmilk by gestational age. Protein stays above the term reference range of 0.9 g/dL beyond when preterm babies reach term corrected gestational age.