Improved Outcomes in Preterm Infants Fed a Nonacidified Liquid Human Milk Fortifier: A Prospective Randomized Clinical Trial.

Objective: To compare growth, feeding tolerance, and clinical and biochemical evaluations in human milk-fed preterm infants randomized to receive either an acidified or a nonacidified liquid human milk fortifier.

Study Design: This prospective, controlled, parallel, multicenter growth and tolerance study included 164 preterm infants (≤32 weeks of gestation, birth weight 700-1500 g) who were randomized to acidified or nonacidified liquid human milk fortifier from study day 1, the first day of fortification, through study day 29 or until hospital discharge.

Results: There was no difference in the primary outcome of weight gain from study days 1 to 29 (acidified liquid human milk fortifier, 16.4 ± 0.4 g/kg/day; nonacidified liquid human milk fortifier, 16.9 ± 0.4 g/kg/day). However, in both the intention-to-treat and the protocol evaluable analyses, infants fed nonacidified liquid human milk fortifier had significantly greater weight gain from study days 1 to 15 (17.9 g/kg/day vs 15.2 g/kg/day; P = .001). Infants fed with acidified liquid human milk fortifier received more protein (4.26 vs  g/kg/day 4.11 g/kg/day, P = .0099) yet had lower blood urea nitrogen values (P = .010). The group fed acidified liquid human milk fortifier had more vomiting (10.3% vs 2.4%; P = .018), gastric residuals (12.8% vs 3.7%; P = .022), and metabolic acidosis (27% vs 5%; P < .001) in the intention-to-treat analysis and more abdominal distension (14.0% vs 1.7%; P = .015) in the protocol evaluable analysis.

Conclusions: Infants fed an acidified liquid human milk fortifier had higher rates of metabolic acidosis and poor feeding tolerance compared with infants fed a nonacidified liquid human milk fortifier. Initial weight gain was poorer with the acidified liquid human milk fortifier.

Trial Registration: ClinicalTrials.gov: NCT02307760.