Longitudinal changes in infant non-nutritive sucking across the first year of life

Non-nutritive suck (NNS; sucking without feeding) is among the earliest oromotor behaviors in infants and has been shown to be associated with future neurodevelopmental outcomes. Prior work has shown that by 12 months, NNS bursts become shorter and stronger compared to 3 months, but when this shift occurs within the first year remains unclear. Twenty-four full-term infants participated in this prospective, longitudinal study with repeated measures at 3, 6, 9, and 12 months. Infants sucked on a custom pacifier with a pressure transducer for ∼5 min. NNS outcomes included burst duration (s), frequency (Hz), amplitude (cmH₂O), bursts/min, cycles/burst, and cycles/min. As infants aged, their NNS patterns changed significantly. By nine months, the suck duration, bursts/min, cycles/burst, and cycles/min had decreased and by twelve months, these measures showed even further reduction, reflecting continued changes in sucking across the first year of life. The most pronounced NNS changes occurred between 6 and 9 months, coinciding with the introduction of solids and a decreased reliance on NNS. These findings highlight when NNS patterns shift during infancy, providing a reference for identifying age-appropriate targets for infants. This study emphasizes the dynamic nature of NNS during infancy and underscores the need for further assessment and exploration of its developmental trajectory.