The Importance of Donor Milk Storage Time for Preemie Gut Health

When selecting food products at the supermarket, consumers often check the "best by" date to ensure freshness and safety. Similarly, a recent study from the Medical University of South Carolina emphasizes the critical importance of storage duration for donor human milk, especially regarding the gastrointestinal health of very premature infants. Published in the Journal of Parenteral and Enteral Nutrition, this research highlights how the storage time of donor milk significantly influences its protective effects for vulnerable preemies.

Lead researcher Dr. Katherine Chetta explained that their findings demonstrated a correlation between longer storage periods and reduced efficacy of donor milk in safeguarding infant gut health. The study involved analyzing medical records of 262 very-low-birth-weight infants who received donor milk at MUSC's neonatal intensive care unit between February 2022 and January 2024. The results showed that with each additional day of milk storage, the risk of developing necrotizing enterocolitis (NEC)—a severe inflammatory bowel disease common among preemies—increased by 3.7%. The optimal frozen storage time was identified as approximately 240 days.

Donor human milk is essential for preterm infants when maternal milk is unavailable or insufficient. It helps decrease the risk of complications like NEC, supports immune function, and aids digestion. NEC, which can lead to bowel tissue death and requires surgical intervention, remains a major concern for neonatal care teams. Although the precise cause of NEC is unknown, it is believed to result from multiple factors including inflammation, bacterial invasion, and immature gut defenses.

Research suggests that the components of donor milk degrade over time, even when frozen. As the milk ages, its protective properties diminish, making it less effective in preventing gut diseases like NEC. Dr. Chetta emphasized that for the most vulnerable preemies—those on the verge of viability or with extremely low birth weights—using fresher milk can significantly improve health outcomes.

Current guidelines from the World Health Organization and CDC advise that frozen donor milk can be stored for up to one year. However, this study indicates that shorter storage times might be more beneficial, especially for critically ill infants. Accordingly, Dr. Chetta's team has already implemented practices in her NICU to prioritize feeding the freshest available donor milk, typically under 240 days old.

This approach involves working closely with milk banks to expedite milk processing and distribution, ensuring that the sickest infants receive the highest quality nutrition. Dr. Chetta advocates for NICUs worldwide to re-evaluate their donor milk storage protocols, aiming to enhance neonatal outcomes through simple yet impactful changes.

In conclusion, this research underscores the importance of milk storage duration and encourages neonatal units to adopt practices that favor fresher donor milk for our most fragile patients. Optimizing storage and handling procedures could be a crucial step in reducing NEC incidence and improving the survival and health of premature infants.