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Donor Milk, Formula Go Head-to-Head for Extreme Preemies in the NICU

— Similar neurodevelopmental outcomes, but less necrotizing enterocolitis with donor milk

MedpageToday
A photo of a premature infant in an incubator.

Whether extremely preterm neonates got nutrient fortified, pasteurized donor milk or preterm formula in the neonatal intensive care unit (NICU) made little difference in neurodevelopmental outcomes, a randomized clinical trial found.

Among newborns fed minimal maternal milk, the adjusted mean Bayley Scales of Infant and Toddler Development (BSID) cognitive score at 22 to 26 months was 80.7 for patients in the donor milk group, similar to the average score of 81.1 in the preterm formula group (adjusted mean difference -0.77, 95% CI -3.93 to 2.39), reported Tarah Colaizy, MD, MPH, of the University of Iowa in Iowa City, and coauthors.

BSID language scores also did not significantly differ between the two feeding groups, nor did BSID motor scores, the double-blind MILK trial published in found.

However, necrotizing enterocolitis was significantly reduced among infants receiving donor milk (4.2% vs 9%). The tradeoff was the finding that weight gain was slower among patients receiving donor milk, at a rate of 22.3 g/kg daily compared with the preterm formula group growing at a rate of 24.6 g/kg daily.

"Overall, the results from the MILK study affirm recommendations (based mainly on reduced risk of necrotizing enterocolitis and without evidence of harm to neurodevelopment) to feed fortified donor human milk to extremely preterm infants when mother's own milk is not available," wrote Mandy Brown Belfort, MD, MPH, of Harvard Medical School in Boston, and Maryanne Perrin, RDN, PhD, MBA, of the University of North Carolina, Greensboro, in an .

"Clinicians caring for infants fed predominantly with donor human milk should respond early when they observe slow weight gain and maximize delivery of protein and micronutrients with current products," the duo urged. "At the same time, researchers must urgently address knowledge gaps about the nutritional composition of donor human milk and its determinants to drive improvements in donor human milk production and processing and to inform fortification strategies optimized for predominantly or exclusively donor human milk diets."

Belfort and Perrin suggested that collection and storage issues may have played a role in the study's results.

"Pasteurization and freezing alter or destroy some milk components. Collecting, storing, and processing milk cause fat loss. Maternal lactation stage also affects donor human milk composition because most milk components decline over time and milk bank donors tend to be at later lactation stages than mothers who have recently delivered preterm infants," the pair wrote.

"For example, donor human milk is considerably lower in protein than mother's own milk after preterm delivery and infant formula because the composition of human milk changes depending on the time from delivery," the editorialists noted.

Study co-author Brenda Poindexter, MD, MS, of the School of Medicine at Emory University in Atlanta, emphasized that moms with preterm babies in the NICU can't do it alone. "We have to support their efforts to provide their own milk, because it is far superior to donor milk or formula."

"Some of these moms have babies that are in the NICU for 4, 5, and 6 months, and a lot of them have to go back to work long before their baby comes home," said told 鶹ý. "So a lot of these moms are tired. They spend their days and nights in the NICU, often with not a lot of privacy and all the things that would really promote milk production. A lot of our moms just don't have that support that they need."

A total of 483 infants were randomized for analysis in the trial, with 239 participants in the donor milk cohort and 244 participants in the preterm formula cohort. Infants from across 15 centers were enrolled from September 2012 to March 2019, with follow-up completed in 2021.

In order to be included in the trial, infants needed to be under 29 weeks gestational age or have a birth weight of below 1 kg (2.2 lbs). Additionally, inclusion criteria indicated that birthing parents either needed to never have initiated lactation, ceased expressing milk before 21 days, or that the parent's daily milk supply was a mean 3 oz or less for 5 days in the period of 7 to 21 days after birth.

The children were randomized to donor milk (fortified using protein supplements or commercially available fortifiers to reach a level of 2.8 g/dL to 3.0 g/dL for protein) or preterm formula. Investigators did not mandate feeding initiation, nutrient fortification practices, and advancement protocols.

Of participating infants, 52% were girls, the median gestational age was 26 weeks, and the median infant birth weight was 840 g. Birthing parents self-reported their racial background, with Black patients making up 52% of the population and white patients making up 43%.

Prior to follow-up, 54 infants in the trial passed away, which left 376 infants available for assessment. Mortality, here defined as death before follow-up, reached a similar 13% among donor milk patients and 11% among the preterm formula group.

Researchers noted that the trial was concluded early as the result of slow enrollment, a limitation of the trial.

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    Elizabeth Short is a staff writer for 鶹ý. She often covers pulmonology and allergy & immunology.

Disclosures

The study was funded by grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development and from the National Center for Advancing Translational Sciences.

Colaizy had no disclosures. Co-authors reported relationships with Abbott Nutrition, ResBiotic/Alveolus Bio, Shire/Oak Hill Bio, Provepharm, Mead-Johnson/Reckitt, the Catholic Medical Association, the Catholic Medical Guild of Dallas, the Low Birth Weight Development Center, and Thrive Neuromedical.

Perrin reported no disclosures. Belfort reported volunteering for the research advisory board for Mothers' Milk Bank Northeast.

Primary Source

JAMA

Colaizy TT, et al "Neurodevelopmental outcomes of extremely preterm infants fed donor milk or preterm infant formula: A randomized clinical trial" JAMA 2024; DOI:10.1001/jama.2023.27693.

Secondary Source

JAMA

Belfort MB, Perrin M "Delivering on the promise of human milk for extremely preterm infants in the NICU" JAMA 2024; DOI:10.1001/jama.2023.26820.