Ultrasound Imaging of Infant Sucking Dynamics during the Establishment of Lactation

Abstract

Background: Infant sucking problems are frequently implicated in early weaning during breastfeeding, yet our understanding of early sucking dynamics is limited. Objective: This study aimed to describe infant sucking patterns during breastfeeding at secretory activation and determine whether they changed by the time of established lactation. Methods: Sucking patterns and milk intake of 15 breastfeeding infants were assessed on day 3.2 ± 0.8 and later at follow-up, 16.0 (11.3-22.8) days postpartum. Nipple diameters, tongue movement, nipple position, and suck rate during nutritive sucking (NS) and non-nutritive sucking (NNS) were measured from ultrasound scans of the intra-oral cavity during breastfeeding. Milk intake and LATCH scores were also recorded. Results: As the tongue lowered during a suck cycle, the nipple increased in size ( P < .001), milk flowed into the intra-oral space and the nipple moved closer to the hard-soft palate junction ( P < .001). During NS, nipple diameters and the mid-tongue movement were greater than during NNS ( P < .001). As the infant aged, the mid-tongue lowered further ( P = .002), suck rates became faster ( P < .001) and milk intake increased ( P = .004), however, no differences were seen for LATCH scores ( P = .34). Conclusion: Differences in tongue movement between NS and NNS suggest that there is an altered sucking action when milk flow is absent. Similar sucking patterns at day 3 and during established lactation imply that infants have a mature sucking pattern in the early postpartum period.