A recent study conducted by researchers at the Medical University of South Carolina (MUSC) sheds critical new light on the impact of storage duration on donor human milk used in neonatal care, particularly among extremely premature infants. Published in the Journal of Parenteral and Enteral Nutrition, this research reveals an alarming association between prolonged storage of donor breast milk and increased gastrointestinal complications, including necrotizing enterocolitis (NEC), in very low birth weight premature newborns. This groundbreaking work is poised to reshape neonatal nutrition protocols and offers a hopeful pathway toward enhanced survival and quality of life for some of the most vulnerable patients in neonatal intensive care units (NICUs).
Donor human milk, a cornerstone of nutritional support for preterm infants whose mothers cannot provide enough breast milk, has long been recognized for its immunologic and digestive benefits. Supplementing or replacing formula with donor milk reduces risks linked to formula feeding, such as infections and impaired gut development. However, until now, the importance of milk freshness—specifically how long it is stored frozen before being fed—has not been thoroughly investigated. This study fills that critical knowledge gap by examining whether the age of frozen donor milk affects its protective bioactivity and clinical outcomes in preterm infants.
Dr. Katherine E. Chetta, a neonatologist and physician-scientist at MUSC, spearheaded this investigation. Her dual expertise in neonatal medicine and breast milk science enabled a meticulous clinical and laboratory evaluation of stored donor milk’s efficacy. The research leveraged a retrospective case-control design reviewing clinical data from 262 very low birth weight infants admitted to the MUSC Shawn Jenkins Children’s Hospital NICU between February 2022 and January 2024. These infants, all weighing less than approximately 3.3 pounds at birth, were exclusively or predominantly fed donor milk, allowing for a focused assessment of storage duration effects on gastrointestinal morbidity, including NEC.
The results were striking: with every additional day of storage, the odds of developing NEC or spontaneous intestinal perforation rose by 3.7%. These findings challenge established guidelines by the World Health Organization and Centers for Disease Control and Prevention, which currently allow frozen donor milk storage of up to one year. According to Dr. Chetta, the optimal ‘freshness window’ for donor milk to confer maximum gut protection in fragile preemies is approximately 240 days or shorter. This threshold demarcates a critical time after which detrimental biochemical changes in breast milk components begin to undermine its protective qualities.
Biochemical analyses conducted alongside clinical observations revealed a progressive degradation of key milk constituents during frozen storage. These include immune-modulating proteins, growth factors, and enzymes essential to mucosal integrity and anti-inflammatory defense in the immature preterm gut. The cumulative loss of these components compromises the milk’s ability to mitigate inflammatory processes implicated in NEC pathogenesis. Thus, the sheer duration of storage acts as a variable modulating the efficacy of donor milk as a living therapy rather than just a nutritional substitute.
Clinically, these findings hold profound implications. NEC remains a major cause of morbidity and mortality in NICUs worldwide, with limited proven prevention strategies. The identification of milk storage duration as a modifiable risk factor introduces a practical and immediate avenue for intervention. Dr. Chetta’s team has already implemented procedural adjustments in their NICU, prioritizing the use of fresher donor milk for the smallest and sickest infants. These changes reflect a paradigm shift, emphasizing temporal quality control in milk banking logistics, from donor recruitment to milk processing and storage practices.
Moreover, this research underscores the importance of interdisciplinary collaboration between neonatologists, dietitians, milk banks, and clinical researchers to optimize milk handling. By reducing transport times from collection sites to the hospital milk room and revising stock rotation protocols, NICUs can enhance the availability of fresher milk without increasing waste. The study highlights a scalable system intervention whereby milk banks and neonatal units establish tighter integration to preserve the bioactivity of donor milk, ultimately improving neonatal outcomes.
Impressively, this study combined rigorous clinical data analysis with laboratory science, bridging translational gaps that too often hinder pediatric nutrition innovations. It utilized the expertise of the South Carolina Clinical & Translational Research Institute to provide robust statistical validation, ensuring the findings were not merely correlative but support prioritizing milk freshness as a determinant of gastrointestinal health in preterm infants. This level of rigor is a model for future investigations into other nutritional therapies affecting neonatal morbidity.
While the study offers compelling evidence for revising milk storage guidelines, Dr. Chetta emphasizes that it does not advocate discarding older milk unnecessarily; rather, it calls for strategic prioritization and efficient use of fresher milk in those at greatest risk. This nuanced approach balances resource stewardship with patient safety, ensuring sustainable applications of this new evidence across diverse healthcare settings. It invites further research to refine optimal storage durations for different subpopulations and to explore technological innovations in milk preservation.
The wider implications of this study extend beyond NICU walls. It prompts reexamination of nutritional best practices in all contexts where frozen human milk is used, especially for medically fragile infants with compromised immune systems or underdeveloped digestive tracts. It also highlights the intrinsic complexity of breast milk as a bioactive fluid, whose therapeutic properties are sensitive to handling and storage conditions, reinforcing the importance of maintaining its integrity throughout the continuum of care.
In summary, MUSC’s pioneering research advocates for a paradigm shift in neonatal nutrition strategy: prioritizing fresher donor human milk to minimize devastating gastrointestinal complications in preterm infants. This revelation carries the promise of improved survival, reduced long-term sequelae, and enhanced quality of life for preemies globally. As neonatal care continues to evolve, integrating these findings into practice guidelines could rapidly transform standards, making fresh human milk not just a nutritional choice but a vital, time-sensitive clinical intervention.
The Medical University of South Carolina continues to lead forefront research in neonatal science, aiming to safeguard the youngest and most vulnerable patients. With this study, they chart a course toward safer, more effective nutrition that honors the biological complexity of breast milk and the delicate needs of preterm infants. Clinicians, researchers, and milk banks worldwide will be watching closely as these findings herald a new chapter in the life-saving potential of donor human milk.
Subject of Research: People
Article Title: Donor human milk storage and gastrointestinal morbidities in preterm infants: A case‐control study
News Publication Date: 1-Aug-2025
Web References: http://dx.doi.org/10.1002/jpen.2780
Image Credits: Medical University of South Carolina. Photograph by Julie Taylor.
Keywords: donor human milk, necrotizing enterocolitis, preterm infants, milk storage duration, neonatal nutrition, gastrointestinal morbidity, breast milk bioactivity, milk banking, neonatal intensive care unit, frozen milk storage, infant gut health, neonatal research
