The effect of nursing on the brain activity of the newborn

To determine whether nursing influences brain activity in the newborn and whether there are differences in this respect between breast- or bottle-feeding and pacifier sucking.

Fifty unselected volunteer mothers and their healthy full-term infants, under care in the maternity ward after delivery, served as subjects. Thirty mother-infant pairs were studied in relation to breast-feeding and 20 to bottle-feeding and pacifier sucking. Breast-fed infants were studied between the 1st and 7th day after delivery (mean +/- 2.7 days) and the infants in the bottle-fed group between the 1st and 8th day after delivery (mean +/- 3.3 days).

Qualitative and quantitative electroencephalogram (EEG), electrooculogram, submental electromyogram, and electrocardiogram were recorded before, during and after breast- and bottle-feeding and pacifier sucking.

The amplitude of the EEG increased significantly during breast-feeding in the posterior cortical areas in both hemispheres with a slight predominance on the right. Bottle-feeding caused a similar, but somewhat less marked change. When the breast- and bottle-fed infants were compared, a significant difference was found in only one parameter of the 84 studied. Pacifier sucking had no significant effects on EEG activity.

Nursing effects a change in the brain activity of the newborn. The cortical response to nursing is most probably a result of activation of the neurohumoral mechanisms related to hunger and satisfaction, including the hypothalamic, limbic, and other brain stem structures, which also regulate the sleep-wake cycle and modulate the level of cortical activity with respect to attention and vigilance.