Mother-infant dyads were observed while breastfeeding during their first visit to our laboratory and were observed while bottle-feeding expressed breast milk during their second visit to our laboratory.

Mother-infant dyads were observed while bottle-feeding expressed breast milk during their first visit to our laboratory and were observed while breastfeeding during their second visit to our laboratory.

Infants will be breastfed during one lab visit and bottle-fed (with expressed breast-milk) during the other.

For both breast- and bottle-feedings, infant intake will be assessed by pre- and post-weighing the baby on an infant scale (model 374; Seca, Hamburg, Germany). During bottle-feedings, we will also note whether the infant finishes the bottle.

Mother and infant behavior during each feeding will be coded using the Nursing Child Assessment Parent-Child Interaction - Feeding Scale (NCAFS). This scale contains six subscales, four of which describe maternal attributes (Sensitivity to Cues, Response to Child's Distress, Social-Emotional Growth Fostering, and Cognitive Growth Fostering) and two of which describe infant attributes (Clarity of Cues and Responsiveness to Caregiver). The proposed analysis will focus on the Sensitivity to Cues subscale, which measures the degree to which the mother is able to understand and respond to her child's cues. This scale provides a global measure of how sensitive the mother is to the infant's needs during the feeding interaction. Possible score range is 0-16, which is derived from summing together maternal scores for each of the 16 subscale items. Higher scores indicate greater sensitivity to infant cues.

This was a within-subject study; all mother-infant dyads (47 mothers + 47 infants = 94 participants total) were exposed to both conditions and the order of presentation was counterbalanced across dyads. Because all dyads were randomized to receive all interventions, all will be combined into one arm/group for the summary that follows.

Mode of Feeding (breastfeeding versus bottle-feeding): Infants will be breastfed during one lab visit and bottle-fed (with expressed breast milk) during the other.

Mother Age at Study Entry

Data are for mothers only (n = 47)

For both breast- and bottle-feedings, infant intake will be assessed by pre- and post-weighing the baby on an infant scale (model 374; Seca, Hamburg, Germany). During bottle-feedings, we will also note whether the infant finishes the bottle.

Mother-infant dyads were observed while breastfeeding during one visit to our laboratory and bottle-feeding expressed breast milk during the other. All mother-infant dyads participated in both conditions. Adverse Event data are reported for mothers (n = 47) and infants (n = 47) separately.