Micronutrient and Macronutrient Composition of Breastmilk from Women Delivering Prematurely

Abstract

Objective: The objective of this study was to measure the macronutrient and micronutrient composition of breastmilk expressed by mothers, including African-American women, delivering preterm infants < 33 weeks gestational age. Our second objective was to use mother’s milk data to determine if preterm breastmilk (lactation day 7 and 28), and donor breastmilk fortified with four commonly available human milk fortifiers met the minimum recommended range of nutrients for the preterm infants. Methods: We collected breastmilk samples from mothers of preterm infants admitted to the NICU at Augusta University Medical Center (AUMC) from January-November 2019. Mother’s milk samples were collected on post-partum days 7, 14, 21, and 28 and analyzed for macronutrients and micronutrients. Using the nutrient data (means) in preterm breastmilk at lactation days 7 and 28, we calculated the nutrient composition of the fortified preterm breastmilk and donor breastmilk after the addition of four commercially available fortifiers; Enfamil® Human Milk Fortifier High Protein Liquid (EHP) (Evansville, IN), Enfamil® Human Milk Fortifier Standard Protein Liquid (ESP) (Evansville, IN), Similac® Human Milk Fortifier Hydrolyzed Protein Liquid Concentrate (SLP) (Columbus, OH), Prolacta +4 H2HMF® (PRO4) (City of Industry, CA). Results: Thirty-eight mothers, average age 27 ± 5.1 years and majority African-American (66%) provided milk for the study. The average EGA and birthweight was 28.2 ± 2.8 weeks and 1098 ± 347 grams respectively, with 42% of infants in the cohort delivering prior to the 28th week of pregnancy. Differences in protein, sodium, potassium, calcium, phosphorus, and zinc concentration based on race, day, and milk volume were identified. Dilution effects for protein, sodium, and chloride, and vitamin D concentration over time were identified. Recommended levels of energy, calcium, phosphorus, and potassium were met with the addition of all four fortifiers. Sodium, chloride, magnesium, Vitamin D, and zinc failed to meet recommendations for mature milk or donor milk and additional supplementation of these nutrients may be warranted Conclusion: Nutrient concentration in preterm breastmilk depends on numerous factors including race, volume of milk produced, lactation stage, and gestational age. These factors should be considered when developing feeding plans for preterm infants.