Preemies Grow Faster With Liquid Human Milk Fortifier

Elizabeth DeVita-Raeburn

September 17, 2012

September 17, 2012 — Premature babies fed breast milk augmented with a highly concentrated, high-protein liquid human milk fortifier experienced more growth and weight gain than those fed with a powdered product commonly used in neonatal intensive care units (NICUs), according to a study published online September 17 in Pediatrics.

The product represents a potential advance because it avoids the use of powder (which can harbor bacteria) and increases the level of protein in the food consumed by these small babies. Research suggests that premature infants have a great need for protein to gain weight and grow. In fact, "[n]ew expert recommendations suggest that preterm infants with birth weights < 1 kg receive 4.0 to 4.5 g/kg per day of protein (3.6–4.1 g/100 kcal)," explain the researchers.

In a multicenter, third party–blinded, randomized controlled prospective trial, Fernando Moya, MD, president of Coastal Carolina Neonatology in Wilmington, North Carolina, and colleagues gave 150 preterm infants weighing 1250 g or less either a powdered fortifier or the liquid fortifier, which contains approximately 20% more protein than the powder fortifier. Both fortifiers are made by Mead Johnson Nutrition and were added to human expressed and/or donor breast milk.

The infants stayed on the protocol for 28 days or until they were discharged from the hospital or graduated to fortifier-free feedings, whichever occurred first. In all, 106 infants stayed on the study for a full 28 days.

Weight and linear growth rate were significantly higher in the liquid vs the powder groups at the end of the 28-day study (P = .04 and P = .03, respectively). Among those who stayed on the protocol the longest, those who received the liquid fortifier had higher weight, length, head circumference, and linear growth rate then the control patients (P = .004, .003, .043, and .01, respectively), according to the study.

Both groups of infants tolerated the 2 fortifiers equally well, and there was no difference at the rate at which they were able to graduate to full feedings. Prealbumin, albumin, and blood urea nitrogen (BUN) were higher in those receiving the liquid fortifier (P < .05).

Premature babies are prone to necrotizing enterocolitis, and the risk is increased when they are exposed to cow milk protein, Nancy Hurst, PhD, RN, director of Women's Support Services and the Mothers' Milk Bank at Texas Children's Hospital and assistant professor of pediatrics at Baylor College of Medicine, Waco, Texas, told Medscape Medical News. Dr. Hurst was not involved in the study.

The smaller the baby, the greater the risk, Dr. Hurst explained. The liquid fortifier is made from cow's milk. "For bigger babies, where we're not as concerned about possible exposure to cows milk protein, certainly this is an advance," she said.

Fortifiers have long been used to augment breast milk in preterm infants, because they have been shown to improve the babies' growth rate.

"These babies are so small that you can't give them a lot of volume. You have to increase the calories in the small volume of milk you give them," Dr. Hurst said.

However, there has been lingering concern about the possibility of contamination in powder-based fortifiers in this vulnerable population because Cronobacter spp (formerly Enterobacter sakazakii), which can be deadly to infants, has been found in powdered baby formula.

So far, the bacteria have not been found in powdered fortifiers, but both the Centers for Disease Control and Prevention and the Academy of Nutrition and Dietetics have recommended against the use of powder fortifiers in NICUs as a precaution.

Many milk fortifiers currently used in NICUs also do not meet the protein needs of these infants, the authors note.

"The frequent lack of tolerance of enteral nutrition for weeks after birth combined with a high-protein turnover rate results in a cumulative protein and energy deficiency in many preterm infants," the authors write. Previous research, they note, suggests that "even a small deficit in protein intake impairs both growth in lean body mass and linear growth."

The authors conclude, "[A]dministration of a higher protein content resulted in a significantly greater BUN, but this had no adverse clinical consequences and remained within the normal limits for this population."

There was no difference between the 2 groups in the incidence of necrotizing enterocolitis or sepsis.

A limitation of the study was that the researchers were unaware of the protein content of the breast milk fed to the infants. The protein content can vary depending on the donor and the time of day it was expressed.

The study was funded by Mead Johnson Nutrition. Two coauthors are employees of Mead Johnson Nutrition. The institutions of Dr. Moya and one coauthor were provided funding to defray the costs of the study. Dr. Moya received travel funds to present data from the study at the International Conference on Nutrition and Growth. Dr. Hurst has disclosed no relevant financial relationships.

Pediatrics. Published online September 17, 2012. Abstract