• Breast feeding;
  • Neonatal behavior;
  • Mother-infant behavior;
  • Polygraphic study


Forty-six normal newborn infants were studied at the age of 6 to 7 days. Each infant was at first breast fed and at the next session was given a bottle feeding of the same amount of expressed breast milk on the same day. The neonatal behavior was assessed over two three-hour periods following each feeding, during which continuous polygraphic recordings and observations were made. Our study consisted of four steps: an expressed breast milk bottle feeding (step 1), an equal holding time period (step 2), an equal sucking time period (step 3), and an equal holding and sucking time period using two kinds of bottles (step 4). Infants who were breast fed had a longer period of quiet sleep and slow heart rate in active sleep compared with those who were bottle fed.

In step 4, there were no significant differences in the amount of quiet sleep and low heart rate in active sleep between breast and bottle feeding. From our results, each component of breast feeding alone such as the breast milk itself, the holding time, or the time for sucking does not have any specific positive influence on neonatal behavior.

Rather, the study suggests that the total mother-infant interaction during breast feeding results in positive influences on neonatal behavior.