Distinct gastroesophageal reflux characteristics in preterm-born infants fed human milk versus formula: insights for clinical practice on outcomes

Objective To compare the characteristics of gastroesophageal reflux (GER) and clinical outcomes among human milk-fed vs. formula-fed infants evaluated for GER disease (GERD). Methods Preterm-born infants ( N = 316, 30.1 ± 3.4 weeks gestation) referred for 24-h pH-impedance testing at 39.8 ± 1.4 weeks postmenstrual age. GER characteristics, short- and long-term outcomes were compared between the human milk- vs. formula-fed infants. Results Human milk-fed infants (vs. formula-fed) had a greater acid reflux index (ARI), and an increased number of acid reflux events, prolonged acid events, and greater proximal acid exposure ( P < 0.05). There were no differences ( P > 0.05) in symptoms, acid clearance, bolus clearance, distal baseline impedance, and discharge outcomes. Bayley composite scores at 2 years were distinct ( P < 0.05) for the distribution (%) of receptive and fine motor skills, favoring human milk-fed infants. Conclusions Despite the pathophysiology caused by acid-GER events, human milk properties may provide better adaptation and modulation of neurosensory and neuromotor responses upon esophageal provocation.