Longitudinal Changes in Suck-Swallow-Breathe, Oxygen Saturation, and Heart Rate Patterns in Term Breastfeeding Infants

Background: Despite the differences in breastfeeding and bottle-feeding, our understanding of how suck-swallow-breathe (SSwB), oxygenation, and heart rate patterns change as the infant ages is based predominantly on bottle-feeding studies. Therefore, this study aimed to measure how SSwB, oxygenation, and heart rate patterns changed during the first 4 months of lactation in term breastfeeding infants. Methods: Infants less than 1 month postpartum (n = 15) were monitored early in lactation and again later in lactation (2-4 months postpartum). Simultaneous recordings of vacuum, tongue movement, respiration, swallowing, oxygen saturation, and heart rate were made during both nutritive sucking and non-nutritive sucking during breastfeeding. Results: Infants transferred a similar amount of milk ( P = .15) over a shorter duration later in lactation ( P = .04). Compared to early lactation, suck bursts became longer ( P < .001), pauses became shorter ( P < .001), vacuum levels decreased (all P < .05), oxygen saturation increased ( P < .001), and heart rate decreased ( P < .001) later in lactation. Conclusion: This study confirmed that term infants become more efficient at breastfeeding as they age, primarily by extending their suck bursts and pausing less. Although infants demonstrated satisfactory SSwB coordination during early lactation, they showed a level of adaption or conditioning at later lactation by applying weaker vacuum levels and demonstrating improved cardiorespiratory responses.