Breast feeding and neonatal behavioral state.

18 normal newborn infants were studied at the age of 5-6 days. Each infant was given breast or bottlefeeding in 2 different sessions on the same day. The newborn assessment was also done in these 2 3-hour sessions, in which sucking and behavioral state were determined. 10 of 18 infants were found to fall asleep soon after the breastfeeding, and to have more quiet sleep and less waking than after bottlefeeding. All of the mothers showed good breast-milk secretion when examined. The other 8 infants, who were not given enough milk, did not show the abovementioned tendency. These results suggest that breastfeeding exerts good influences on neonatal behavior.