Heart rate variability in premature infants during feeding.

Early mother-infant interaction, a potentially major contributor to the development of a premature infant's behavioral and physiologic regulation, has received very little research attention. This study examined the development of physiologic regulation in relation to maternal-infant feeding interaction for 43 premature infants, from the time caregiving responsibility was transferred to the mother through each infant's 4th postterm month. Infants and mothers were seen in a special care nursery just before discharge and in home at 1 and 4 months postterm age. General linear mixed models were used to examine the changes in infant heart rate variability (HRV) and Positive Affective Involvement and Sensitivity/Responsiveness scores over time and infant HRV over feeding conditions (prefeeding, feeding, and postfeeding). Significant differences were found for high-frequency and low-frequency HRV over time (p < .001 and p = .014, respectively). However, maternal feeding behavior did not show a significant effect of time (p = .24). The feeding condition effect on high-frequency HRV was significant (p < .001), with HRV lower during feeding compared to both prefeeding and postfeeding. Maternal feeding behavior was not associated with infant HRV. Discovering the ways in which maternal feeding behavior contributes to infant physiologic regulation may require study of the relationship of HRV to infant feeding behavior.