Donor human milk saves lives for preterm babies when a mother’s own milk isn’t available, but new research suggests not all donor milk is the same. An international study led by UNC Greensboro has found major differences in the nutritional makeup of donor milk across countries, variations that could shape how hospitals fortify and deliver milk to vulnerable newborns.
“Donor human milk serves as a lifesaving feeding alternative for preterm infants when a mother’s own milk is unavailable, significantly reducing the risk of necrotizing enterocolitis — a devastating intestinal condition,” said Maryanne Perrin, PhD, associate professor of nutrition at UNCG and lead author of the study. “Our study reveals current clinical protocols around donor human milk may require substantial revisions that vary based on the profile of a milk bank’s donors.”
The team analyzed 600 samples from eight milk banks in Chile, Kenya, Poland, Vietnam and the United States. In most countries, donors gave milk several months after birth, producing samples higher in lactose and certain B vitamins. But in Kenya, donations were collected within two weeks of delivery, often from mothers of preterm infants. Those samples contained 30–50% more protein, along with higher levels of minerals like iron, zinc and selenium, nutrients especially critical for fragile babies.
Regional differences also showed up in vitamins, likely reflecting local diets. For example, U.S. samples had relatively higher riboflavin but lower choline, while Polish samples were lower in vitamin B12.
“Donor human milk is usually fortified to ensure vulnerable preterm infants receive the best possible nutrition,” Perrin said. “Our findings imply that these fortification strategies could be optimized according to specific regions and milk-banking models.”
The study, published in the American Journal of Clinical Nutrition, highlights both progress and challenges. While milk banking has expanded globally, more than 60% of nutrient variation in the study could not be explained by donor age, lactation stage or storage factors. Perrin and colleagues suggest strategies such as pooling milk from multiple donors to help reduce variability and ensure consistency.
This study is the largest and most geographically diverse analysis of donor human milk to date, filling key knowledge gaps by including low- and middle-income countries with high preterm birth rates.
With 15 million preterm babies born each year, researchers say better tailoring of donor milk protocols could help improve survival and long-term outcomes for some of the world’s most vulnerable infants.
This study was funded by the National Institute of Child Health and Human Development. Additional support came from the Family Larsson-Rosenquist Foundation. Authors reported advisory and coordinating roles with the Human Milk Banking Association of North America and the World Health Organization.