Early development of the infant begins in utero and at 13 weeks post-conception the swallow emerges. By 18 weeks post-conception the infant is able to suck on his hands. When the infant is born prematurely we anticipate that by 32-34 weeks gestation or PCA the coordination of suck and swallow will be developed. Unfortunately, in many nurseries when this is observed it is interpreted as a sign that the infant is ready to be bottle-fed. Although the infant is able to suck and swallow, one very significant component of “the total sucking activity” has not yet developed and that is the coordination with respiration. Because these preterm infants at 32-34 weeks PCA have not yet developed the neurological maturation or the respiratory support, they are not able to demonstrate enough coordination of suck/swallow/breathe to be able to be successful oral feeders. This coordination develops around 37 weeks PCA or later. This misconception also occurs when an infant is observed demonstrating a non-nutritive suck on either a pacifier or his fingers. This is interpreted as the infant is ready to feed and may serve as a detriment to the infant since feeding the infant before he is able to demonstrate a coordinated suck/swallow/breathe pattern may be very stressful and, therefore, subsequently hold him back rather than to help him to progress in the area of oral feeding.
At the moment when the pharyngeal swallow occurs the infant stops breathing so as to allow the bolus to go down the esophagus rather than to be inhaled into the trachea. Sometimes very young infants who are being bottle-fed are not able to start breathing again once respiration has been paused for the pharyngeal swallow. This pause in respiration is called deglutition apnea and occurs frequently in the premature infants. As the infant matures and develops the incidence of deglutition apnea decreases. Episodes of apnea will cause oxygen saturation levels to drop and should be an indication that the infant is not ready for oral feeding. (Hanlon, MB. Et.al., “Deglutition ap0noea as indicator of maturation of suckle feeding in bottle-fed preterm infants” Developmental Medicine & Child Neurology, 1997, 39, 534-542.) In fact, it has been reported that episodes of deglutition apnea remain more frequent in premature infants reaching term compared to term infants.
Maturation of the neurologic system and the respiratory status have more influence on the developmental process than do early experience or practice. It has been reported that when an infant is fed too early and is stressed, it takes approximately 22 days longer for that infant to transition onto full oral feeds than the infant who is not stressed by being pushed to eat too early. (Yi, YG, Oh, BM et.al., “Stress signals during sucking activity are associated with longer transition times to full oral feeding in premature infants” Frontiers in Pediatrics, 2018, 12:6, p. 5) We should also be aware that a decrease in ventilation during sucking has been reported and that this does improve with maturation.
Preterm infants frequently have difficulty with the coordination of suck, swallow, and breathe and will present with a disorganized suck pattern. The number of sucks per burst will be too variable, or the infant presents with bursts of 5-10 sucks which is indicative of a disorganized suck. When the infant is closer to term and is able to demonstrate over 10 sucks in every sucking burst but unable to maintain a consistent suck/swallow/breathe ratio this pattern would also be diagnosed as disorganized. In all cases the disorganized suck is caused by the inability to coordinate the suck and swallow with respiration.
We now know that early sucking performance is predictive of later developmental outcome and that sucking performance is related to neurodevelopment and maturation so let’s see if we can be patient with our little ones and wait just a bit longer to introduce oral feeding to these preterm infants. Remember if your baby is stressed by feeding it will take him longer to transition to full oral feeds. Just the opposite result of where you thought he was headed: to full oral feeds and an earlier discharge.
Marjorie Meyer Palmer MA, NLP, CCC-SLP, Neonatal / Pediatric Feeding Specialist, Speech-Language Pathologist, Founder / Director NOMAS® International
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