An understanding of the suck cycle can empower parents and HCPs to assess effective suck and successful milk transfer, especially in the early days.
With active flow of breastmilk to the infant, sucking and swallowing occurs at least once per second. This frequency increases if the milk flow increases or reduces.
It is normal for sucking at the initiation of a breastfeed to occur in short and fast bursts, these may feel like a tugging but should quickly progress to long and continuous sucking as the milk flow establishes.
Prior to Lactogenesis II, swallowing will be irregular, but after secretory activation, on average from day 4 of life, a pattern will be noted whereby the infant begins the feed with a quick burst of sucking, as she stimulates the milk ejection reflex, to a more sustained suck:swallow:breathe pattern after the milk ejection reflex or ‘let down’ occurs. It is important to note that this part of the cycle is highly variable and the ratio between each component of the suck:swallow:breathe pattern is rarely 1:1:1.
This phase of the pattern can last for over two minutes and the infant may then pause and repeat the cycle. The initial sucks are quick and tugging, whereas the sucks in the second phase of active milk flow are longer and more rhythmic.
Newborns breathe through their noses and will breathe throughout feeding. It is important when assessing the latch to ensure that the nose is free without having to move the breast tissue away to allow the infant to breathe freely.