Mothers of breast fet preterm infants (n=14, BW 1617 +/- 240g, GA 32 +/- 1 wk, 5′Apgar 8 +/- 1) were more responsive to their infants' social initiatives and provided more social stimulation one month post discharge than mothers of formula fed premature infants (n=20, BW 1656 +/- 444g, GA 32 +/- 2 wks, 5′ Apgar 7 +/- 2).

Infants were enrolled within twenty four hours of hospital admission. Mothers who wished to breast feed were assisted with information about producing and storing their milk. Thirty minute observations of maternal-infant interactions were conducted by blinded examiners during home visits one month after discharge. In fifteen second epoch, the presence of specific behaviors were recorded for each mother-infant dyad.Table

Table 1

The breast fed group exhibited significantly (p<0.05) more interactive behaviors per infant. This enhanced responsiveness of breast feeding mothers was evident in both low and middle class socioeconomic groups. We speculate that the long term developmental advantage associated with breast feeding may be mediated by maternal behavior in addition to the nutritional properties of the breast milk.