The first nutritive sucking responses of premature newborns

In order to begin to understand how age, weight, experience, and neurobehavioral development affect feeding in preterm (PM) infants, we recorded milk consumption, length of the feeding session, and two parameters of sucking (rate and amplitude) in FM infants during their first bottte-feeding experiences. In Study 1, we examined how the sucking of PM and full-term (FT) infants varies in its strength, probability of occurrence, and efficiency. In Study 2, we examined how these sucking parameters change in the PM infant during the first few days of life. We found that PM and FT infants differed in their ability to suck and withdraw milk from the bottle, even if they have had equivalent lengths of stay in the Special Care Nursery of North Central Bronx Hospital, and even when they have had equivalent, though limited, prior feeding experience. PM infants were unlikely to bottle-feed successfully until about 35 weeks postconceptional age. Once PM infants had begun to bottle-feed, the parameter of sucking which best differentiated them from FT infants was amplitude. Ten days after the initiation of bottlefeeding, PM infants sucked at a higher rate and with somewhat greater force than they displayed during their first feedings. This improvement over time may be a function of experience or age, or both. Finally, and surprisingly, healthy FT infants fed by their own mothers consumed milk more slowly than did slightly ill FT infants fed by staff nurses, even though they sucked as forcefully and as often as the FT infants fed by the nurses. This finding may be the result of the different ways the mothers and nurses fed the infants.