Opaque Bottle Study

The overall objective of the proposed pilot/feasibility study is to evaluate a home- and
family-based intervention to increase formula-feeding mothers' responsiveness to infant
satiety cues and moderate formula-feeding infants' rates of weight gain over a 12-week
period. Specifically, the investigators propose to provide mothers with opaque, weighted
bottles (instead of conventional, clear bottles) with which to feed their infants; based on
preliminary studies, it is hypothesized that removal of mothers' abilities to assess the
amount the infant consumes during a feeding will facilitate abilities to feed in response to
infant satiation cues.

For the proposed research, exclusively formula-feeding mothers with <8-week-old infants will
be randomized to use weighted, opaque bottles (intervention or opaque group) or to use clear
bottles (control or clear group). The investigators will conduct home-based assessments at
the beginning and end of the 12-week study period during which mothers will be video-recorded
feeding their infants using clear or opaque bottles. Two interim assessments will be
conducted (after 2 and 6 weeks) to assess feeding adequacy and fidelity to the intervention.
During feeding observations, infant intake will be assessed via bottle weight. Video-records
will be later coded for maternal responsiveness to infant cues using the Nursing Child
Assessment Parent-Child Interaction Feeding Scale (NCAFS). It is hypothesized that mothers in
the opaque group will feed their infants less and show greater increases in their levels of
responsiveness to infant cues compared to mothers in the clear group. Infants' weight and
length will be measured at the beginning and end of the 12-week study; weight-for-length
z-scores (WLZ) will be calculated using the WHO Growth Standards. It is hypothesized that WLZ
change will be significantly lower for infants in the opaque compared to the clear group. The
feasibility of the intervention will also be explored by collecting and analyzing objective
and subjective data related to the extent to which mothers use and like the bottles, and
whether characteristics of mothers or infants moderate intervention effects. The proposed
feasibility study is a critical step toward understanding mothers' acceptance and use of
opaque bottles compared to conventional, clear bottles, and the potential for opaque bottles
to improve the outcome of feeding interactions in home-based settings.

Inclusion Criteria:

- mothers 18-40-years of age

- infants <8-weeks of age

- exclusive formula-feeding

- mother predominantly or solely responsible for infant feeding

- dyad has a pediatrician and plans to attend infant well-visits

- mother is willing to use stainless-steel bottles and to provide the study with her
current bottles, which would be returned after study completion

- prior to the introduction of solid foods.

Exclusion Criteria:

- preterm birth (i.e., gestational age <37 weeks)

- low birth weight (<2500 g)

- maternal smoking during pregnancy

- current or past medical conditions that interfere with oral feeding

- history of slow growth or failure to thrive

- weight for length percentile <5th

- diagnosed developmental delay (e.g., Down's syndrome)

- currently using opaque bottles