Comparison of physiological and behavioral responses to fresh and thawed breastmilk in premature infants - A preliminary study

Background: Breastmilk is usually frozen for premature infants when they are unable to feed orally. However, thawed breastmilk may have altered odor and taste from its original form. Few studies have investigated whether premature infants respond differently to fresh and thawed breastmilk. The purpose of this study was to examine the physiological and behavior responses of premature infants alternately fed fresh and thawed breastmilk. Subjects and Methods: An experimental, crossover study using random assignment was conducted. A convenience sample of 18 premature infants less than 37 weeks gestational age at birth with the capability of oral feeding was studied. The premature infants were fed with fresh and thawed breastmilk during two consecutive meals in a random order. Infants' heart rate and oxygen saturation levels were measured baseline and during feeding, as well as observed feeding cues during the feeding period. Results: Premature infants showed significant differences in heart rate when fed thawed, as opposed to fresh, breastmilk. Premature infants demonstrated more stress cues when fed thawed compared with fresh breastmilk (p=0.007). For infants with postmenstrual ages greater than 36 weeks gestation, feeding with thawed breastmilk showed more stress cues and greater effect on heart rate activity compared with fresh breastmilk (p<0.05). Conclusions: Older premature infants demonstrate more stress when fed with thawed breastmilk. Preterm infants should be directly breastfed or fed with nonfrozen breastmilk, when they show stress behaviors in being fed with thawed breastmilk.