Effects of opaque, weighted bottles on maternal sensitivity and infant intake

A Pilot Feasibility Randomized Controlled Trial of Effects of Opaque Bottles on Maternal Sensitivity, Infant Intake, and Infant Weight Status

BACKGROUND

Conventional clear infant feeding bottles provide visual cues about the amount of milk consumed, which may decrease caregivers' sensitivity to infant cues, increase infant intake, and lead to greater infant weight gain.

OBJECTIVE

This study examined feasibility, adherence, acceptability, and preliminary effectiveness of an intervention in which families received clear vs opaque bottles.

DESIGN

A pilot feasibility randomized controlled trial was conducted.

PARTICIPANTS/SETTING

Participants included mothers (N = 76) with young infants (2.9 ± 1.4 months old). Data collection occurred between December 2018 and July 2022 and within San Luis Obispo and Santa Barbara Counties, California. All assessments occurred within participants' homes.

INTERVENTION

Participants were randomized to use clear (Clear group, n = 38) or opaque (Opaque group, n = 38) bottles for 12 weeks.

MAIN OUTCOME MEASURES

We assessed feasibility of recruitment and retention, participant perceptions of study bottles, participant adherence to the intervention, maternal sensitivity to cues, infant intake (mL and mL/kg), and infant weight-for-length z-scores (WLZ).

STATISTICAL ANALYSES PERFORMED

Data were analyzed using linear regression, χ2 analysis, and repeated-measures analysis of variance (ANOVA).

RESULTS

Of 842 potential participants, 295 (35%) could not be reached after initial contact, 166 (20%) declined to participate, and 305 (36%) were ineligible. Of those who declined, 16 (10%) declined because they did not want to use study bottles. No differences were observed for loss to follow-up for Clear (8 of 38; 21%) vs Opaque (5 of 38; 13%) groups (P = 0.36) or for reported use of assigned bottles for Clear (89.8% ± 24.5% of daily feedings) vs Opaque (90.1% ± 22.1%) groups (P = 0.96). No group differences were observed for sensitivity to cues (P = 0.52) or intake (mL, P = 0.53 or mL/kg, P = 0.56) at follow-up. Opaque group infants had lower WLZ at follow-up compared with Clear group infants (mean difference, 0.47; 95% confidence interval, 0.08, 0.86; ηp2 = 0.17), adjusting for baseline WLZ.

CONCLUSIONS

Relative to providing clear bottles, providing families with opaque bottles appeared feasible and acceptable, with good adherence. Although preliminary, study findings suggest the potential of opaque bottles to support healthier weight outcomes for bottle-fed infants.

Formula Feeding Is Associated with Rapid Weight Gain between 6 and 12 Months of Age: Highlighting the Importance of Developing Specific Recommendations to Prevent Overfeeding

We examined differences in mean daily calorie intake and rapid weight gain risk among 6- to 12-month-old infants by milk feeding status: breastmilk only, breastmilk and formula (combined), or formula only. Another objective was to determine what frequency and amount of formula fed were associated with overfeeding among infants. Mother-infant dyads (n = 240) were recruited from a pediatric clinic mainly serving Medicaid recipients. At 6, 9, and 12 months of infants' age, 24 h feeding recalls were conducted using the multiple-pass method. Infant weight measurements were accessed from clinic records to estimate rapid weight gain between 6 and 12 months. Among the participants, 82% received WIC. More than half of the participants were either African American or Latino by race/ethnicity. Calorie intake among formula-only fed infants was higher than in the other two milk feeding groups. One-fourth of the infants were experiencing rapid weight gain, and the risk was 3-fold higher among formula-only fed infants. Exceeding daily calorie requirements or overfeeding was associated with both formula amount and the frequency of feeding (p < 0.01). Specific guidelines and education on formula feeding practices are critical to prevent accelerated growth among infants. Gaining further understanding on parenting style and formula feeding practices is also warranted.

Comparison of mothers' perceptions of hunger cues in 3-month-old infant under different feeding methods

BACKGROUND

Mothers' perception of infant hunger cues is a critical content of responsive feeding, which is central to the promotion of early childhood development. However, only a few studies have examined responsive feeding in China, especially lacking the studies on perceptions of infant hunger cues. Consider the cultural differences, the aim of this study was to describe the perceptions of infant hunger cues of Chinese mothers for infants aged 3 months, and explore the relationship between maternal perceptions of infant hunger cues and different feeding methods.

METHODS

A cross-sectional study was conducted with a sample of 326 mothers of healthy 3-month-old infants, including 188 exclusive breastfeeding (EBF) mothers and 138 formula feeding (FF) mothers. It was implemented in four provincial and municipal maternal and child health hospitals. The mothers' perceptions of infant hunger cues were surveyed by self-reporting questionnaires. Chi-square tests and logistic analysis were applied to analyze the differences in maternal perceptions of infant hunger cues, including the number of hunger cues and the specific cues, between EBF group and FF group by controlling sociodemographic variables and the daily nursing indicators.

RESULTS

We found that a higher proportion of EBF mothers could perceive multiple hunger cues (≥ 2) than FF mothers (66.5% vs.55.1%). For specific cues, the EBF mothers had higher perceptions of infant's "hand sucking" (67.6% vs. 53.6%) and "moving head frantically from side to side" (34.6% vs. 23.9%), all p < 0.05. Regression analysis revealed that EBF might support mothers to perceive infant hunger cues than FF mothers, with the number of infant hunger cues (OR = 1.70, 95% CI: 1.01-2.85), "hand sucking" (OR = 1.72, 95% CI: 1.04-2.87), "moving head frantically from side to side" (OR = 2.07, 95% CI: 1.19-3.62). The number of infant hunger cues perceived by mothers was also associated with their educational level and family structure.

CONCLUSION

EBF mothers of 3-month-old infants may be more likely to perceive infant hunger cues than FF mothers in China. It is necessary to increase the health education about infant hunger and satiety cues to caregivers in China, especially among mothers with lower education levels, mothers living in nuclear families, and FF mothers.

Infant Age Moderates Associations between Infant Temperament and Maternal Technology Use during Infant Feeding and Care

Previous research illustrated that infants' temperamental traits shape parents' behaviors, but parents' behaviors can also elicit or intensify infants' behaviors in ways that shape temperament. One understudied aspect of parenting that may exhibit bidirectional influences with temperament is parent technology use (e.g., use of mobile devices) within family contexts. To date, few studies have examined whether maternal technology use is associated with infant temperament and whether age-related differences in these associations exist. The present study was a secondary analysis of pooled data from three infant feeding studies. Mothers (n = 374) of young infants (age 16.2 ± 6.2 weeks) completed measures of maternal technology use during infant feeding and care interactions, infant temperament, and family demographics. Maternal technology use was positively associated with negative affectivity and negatively associated with orienting/regulatory capacity but was not associated with positive affectivity/surgency. The association between maternal technology use and negative affectivity was stronger for younger infants than older infants, while the association between maternal technology use and orienting/regulatory capacity was not significant for younger infants but was for older infants. Findings suggest maternal technology use is associated with infant negative affectivity and orienting/regulatory capacity, but the strength of these associations may change with infant age. Further longitudinal research is needed to verify this interpretation and understand mechanisms underlying these associations.

Strategies to promote responsive bottle-feeding in WIC predict less frequent use of food to soothe and healthier weight status for infants with negative temperaments

BACKGROUND

Infants with greater temperamental negative affectivity are at higher risk for overfeeding and excess weight gain.

OBJECTIVE

To examine whether strategies to promote responsive bottle-feeding within WIC promoted healthier maternal feeding practices and infant weight status among infants with greater negative affectivity.

METHODS

Secondary analysis of data from a matched-pair cluster randomized trial. Policy, systems and environmental change (PSE) strategies to promote responsive bottle-feeding were implemented at three WIC clinics; these clinics were compared with three matched control clinics. Linear mixed models tested whether infant negative affectivity interacted with PSE strategies to predict feeding and weight outcomes when infants were 4-6 months old.

RESULTS

Significant interactions between infant negative affectivity and PSE strategies were noted. Among infants with high negative affectivity, mothers in PSE clinics reported less frequent use of food to soothe (p = 0.009) compared with mothers in control clinics. Among infants with moderate (p = 0.008) or high (p = 0.029) negative affectivity, infants in PSE clinics had healthier weight status compared with infants in control clinics.

CONCLUSIONS

Promotion of responsive bottle-feeding is an effective way to support WIC mothers and reduce risk for overfeeding and excess weight gain, particularly for mothers of infants with greater negative affectivity.

Associations between mothers' use of food to soothe, feeding mode, and infant weight during early infancy

Weight status and rate of weight gain in the first six months postpartum are strong predictors of later obesity; thus, infant feeding practices are an important target for obesity prevention efforts. The use of food to soothe (FTS) is associated with less-favorable eating habits and weight outcomes for older infants and children. However, few studies have examined correlates of use of FTS during early infancy. The primary aim of this cross-sectional study was to explore associations between use of FTS and infant weight status in the first 6 months postpartum. A secondary aim was to identify the combination of maternal and infant characteristics that predicted use of FTS. Mothers of infants aged 6 months or younger (N = 134) completed questionnaires assessing use of FTS, bottle-feeding intensity (i.e., percentage of daily feedings from bottles versus directly from the breast), levels of responsive and pressuring feeding styles, dimensions of infant temperament and eating behaviors, and family demographics. Dyads were observed during feeding to assess maternal sensitivity to infant cues and responsiveness to infant distress and infant clarity of cues and responsiveness to the mother. Infant weight and length at study entry were assessed by a trained research assistant. Use of FTS was not associated with infant weight for age z-score (WAZ), even when bottle-feeding intensity was considered as a moderator. More frequent use of FTS was predicted by the combination of greater levels of pressuring feeding style (p = .005) and infant temperamental negative affectivity (p = .001), and lower levels of infant temperamental surgency/extraversion (p = .018). In conclusion, use of FTS was associated with dimensions of infant temperament and maternal feeding style, but not with WAZ during early infancy.

Promoting Responsive Bottle-Feeding Within WIC: Evaluation of a Policy, Systems, and Environmental Change Approach

BACKGROUND

Bottle-fed infants are at greater risk for overfeeding and rapid weight gain (RWG); evidence-based strategies for promoting healthy bottle-feeding practices are needed.

OBJECTIVE

Our aim was to assess whether policy, systems, and environmental (PSE) strategies for promoting responsive bottle-feeding practices within the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) were associated with lower risk for RWG.

DESIGN

We conducted a matched-pair cluster randomized trial. PSE strategies were implemented at 3 WIC clinics in Los Angeles County. PSE clinics were compared with 3 matched control clinics. Mothers and infants were assessed when infants were newborn and 3 months and 6 months of age.

PARTICIPANTS/SETTING

Participants were mothers (n = 246) who enrolled their newborn infants (younger than 60 days) into WIC between May and August 2019.

MAIN OUTCOME MEASURES

Infant weight was assessed and standardized to sex- and age-specific z scores. RWG was defined as weight-for-age z score change > 0.67. Mothers completed questionnaires assessing responsive and pressuring feeding styles, breast- and bottle-feeding patterns, and perceptions of WIC experiences.

STATISTICAL ANALYSES PERFORMED

Logistic regression with estimation via generalized estimating equations and linear mixed models with repeated measures assessed effects of PSE strategies on categorical and continuous outcomes, respectively.

RESULTS

Infants in PSE clinics had significantly lower likelihood of exhibiting RWG (P = .014) than infants in control clinics. Mothers in PSE and control clinics reported similar levels of responsive and pressuring feeding style and similar prevalence of breastfeeding and bottle-feeding. Mothers in PSE clinics trended toward feeling better supported with respect to their decision to bottle-feed (P = .098) and had more stable intentions to stay in the WIC program (P = .002) compared with mothers in control clinics.

CONCLUSIONS

PSE strategies focused on promoting more inclusive assessment of infant feeding, tailored bottle-feeding counseling, and increased education and support for responsive bottle-feeding were associated with lower risk for RWG among WIC infants.

Expectation of parental control and the maintenance of bottle-feeding in childhood

OBJECTIVE

To investigate association between parental locus of control (belief of individuals about what or who has control of the events of their lives) and bottle feeding habits among children from 3 to 5 years of age.

METHODOLOGY

Parental locus of control validated in Brazil, and semi-structured questionnaire to obtain sociodemographic, health, and oral habit behaviors was applied to mothers of 992 preschool children. Outcome variable "use of feeding bottle" was studied according to the time of its use (≤36 months and >36 months). Simple logistic regression models were adjusted and raw odds ratios were estimated for variables of distal blocks, which contemplated parental locus of control, socioeconomic characteristics of family, and maternal habits. In the intermediate block, the variables for conditions of the child's birth and place of health care attendance during the prenatal period and early childhood were included. In the proximal block, the time of breastfeeding and pacifier use were reported. Variables were analyzed from the distal to the proximal block, and the individual analyses that presented p≤0.20 remained in each model; included in the subsequent block were the variables with p≤0.10, because this was a study of prevention.

RESULTS

Longer time of feeding bottle use was associated with the internal parental locus of control, mothers older than 31 years of age, white race, premature children, who used pacifiers and are treated in the private health system.

CONCLUSIONS

Children who maintained the habit of feeding bottle use for a longer time were those whose mother presented an internal locus of control.

Potential overfeeding among formula fed Special Supplemental Nutrition Program for Women, Infants and Children participants and associated factors

BACKGROUND

The Special Supplemental Nutrition Program for Women, Infants and Children (WIC) provides enough formula to meet the known nutritional needs of infants up to 6 months of age whose mothers report not breastfeeding, but many mothers report WIC providing insufficient formula, indicating potential overfeeding.

OBJECTIVE

To estimate the prevalence of potential overfeeding among formula-feeding WIC participants and identify associated factors.

METHODS

Potential overfeeding was identified among participants of the longitudinal Infant and Toddler Feeding Practices Study-2 (ITFPS-2) receiving the fully formula-feeding WIC infant package at 1 month of age (n = 1235, weighted n = 197 079). Associations of potential overfeeding with caloric intake, weight and participant characteristics were assessed.

RESULTS

Potential overfeeding was identified among 37.41% (95% CI = 33.57-41.25%) of fully formula-feeding infants. Potentially overfed infants were 0.18 kg heavier (P-value = .01), consumed 26 more calories daily (P-value = .004) and were more likely Non-Hispanic White or English-speaking Hispanic (P-value = .007) and highly active at 5 months of age (P-value = .01). Mothers of potentially overfed infants were less likely to agree that breastfeeding is easier than bottle feeding, only mothers can feed breastfed infants, turning away from the bottle indicates satiation, and crying always indicates hunger (P-values .04, .002, .04 and .04 respectively), and more likely to report WIC provides insufficient formula early (1-5 months, P-value <.0001) and late (6-13 months, P-value = .007) in infancy.

CONCLUSIONS

Potential overfeeding occurs in 37% of fully formula-feeding infant WIC-participants <6 months old. Mothers of these infants may benefit from additional education about the formula needs of their infants and how to recognize infant satiation cues.

Positive parenting approaches and their association with child eating and weight: A narrative review from infancy to adolescence

Parents play a critical role in the development of children's eating behaviours and weight status, serving as providers, models and regulators of the food environment. Many research reviews have focused on the robust body of evidence on coercive control in feeding: how parenting practices such as restriction and pressure to eat increase children's risk for developing undesirable eating behaviours and unhealthy weight outcomes. Fewer reviews adopt a strengths-based perspective focusing on the ways that parents can actively support the development of healthy eating behaviours and weight trajectories. Emerging research on such positive parenting styles and practices offers solutions beyond the avoidance of coercive control, as well as opportunities to highlight parallels between research on food parenting and the broader, well-established developmental literature on positive parenting. The focus of this review is to summarize what is known regarding benefits of positive parenting styles and practices for child eating and weight outcomes and discuss recommendations for future research. Current evidence supports starting with responsive feeding and parenting during infancy and incorporating structure and limit setting in early childhood, with monitoring and mealtime structure remaining important during middle childhood and adolescence. Areas for future research include: (1) further examination of the implications of identified food parenting practices and styles among diverse groups and caregivers; (2) increased consideration of child factors (eg, temperament) as moderators or mediators; and (3) further clarification of the relationship between general parenting and food parenting.

Is breastfeeding associated with later child eating behaviours?

Individual differences in children's eating behaviours emerge early. We examined the relationship between breastfeeding exposure and subsequent eating behaviours among children from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort. Children (n = 970) were grouped according to their breastfeeding exposure: high (full breastfeeding ≥ 4 months with continued breastfeeding ≥ 6 months), low (any breastfeeding < 3 months or no breastfeeding) and intermediate (between low and high breastfeeding categories). Aspects of eating behaviour from ages 15 months to 6 years were captured using a combination of maternal reports (Child Eating Behaviour Questionnaire; Infant Feeding Questionnaire; Preschooler Feeding Questionnaire) and laboratory-based measures of meal size, oral processing behaviours (e.g. average eating speed and bite size) and tendency to eat in the absence of hunger. Most children had low (44%) or intermediate (44%) breastfeeding exposure; only 12% had high exposure. After adjusting for confounders, multivariable linear regression analyses indicated the high (but not intermediate) breastfeeding group was associated with significantly lower reported food fussiness at 3 years compared to low breastfeeding group (-0.38 [-0.70, -0.06]), with similar but non-significant trends observed at 6 years (-0.27 [-0.66, 0.11]). At 3 years, mothers in the high breastfeeding group also reported the least difficulty in child feeding compared to low breastfeeding group (-0.22 [-0.43, -0.01]). However, high breastfeeding was not associated with any other maternal-reports of child feeding or eating behaviours, and no significant associations were observed between breastfeeding exposure and any of the laboratory measures of eating behaviour at any of the time points. These results do not strongly support the view that increased breastfeeding exposure alone has lasting and consistent associations with eating behaviours in early childhood.

Development and validation of the Maternal Distraction Questionnaire

This paper describes the development of a self-report measure of mothers’ engagement in technological activities during mother-infant interactions. In Study 1, mothers (n = 332; infants: 3.8 ± 1.4 months) completed the Maternal Distraction Questionnaire (MDQ) and related questionnaires. Factor analysis revealed two distinct subscales representing engagement with technological distractors and perceived distraction. Subscales correlated with relevant measures of feeding styles, attachment, and infant eating behaviors and temperament. In Study 2, mothers (n = 24; infants: 3.8 ± 1.8 months) completed the MDQ and kept feeding activity diaries. Significant correlations between MDQ subscales and diary data were noted. In sum, the MDQ is a valid measure of maternal engagement with technological activities during mother-infant interactions.

Bottle-feeding an infant feeding modality: An integrative literature review

Bottle‐feeding is an infant feeding modality that has been in existence since ancient times, and currently, a significant number of infants are being fed via a bottle with either breastmilk or formula. Although research on bottle‐feeding has continued, it exists in fragmented, often small studies that focus on singular aspects of feeding an infant using a bottle, with limited information on the bottle‐feeding act. Systems theory was the approach used to define the act of bottle‐feeding and identify the parts within this act. Health databases were searched using MeSH terms. A summary of the studies are included. The findings of this review revealed that healthy term bottle‐feeding infants use similar tongue and jaw movements, can create suction and sequentially use teat compression to obtain milk, with minimal differences in oxygen saturation and SSB patterns, when compared with breastfeeding infants. Bottle and teat characteristics were revealed to affect infant feeding and milk intake. An infant's milk intake during feeding was shown to have a strong association with the interaction between the infant and parent/caregiver. With the issue of who controls the feed, mother or infant, likely to affect an infant's ability to self‐regulate their milk intake. Redefining bottle‐feeding as a holistic system identifies the interrelationship of the various parts which will improve the understanding of the reciprocal nature of infant feeding. To optimize bottle‐feeding outcomes, further research is required on parents' and health professionals' knowledge and understanding of the parts within the act of bottle‐feeding.

Exploration of Responsive Feeding During Breastfeeding Versus Bottle Feeding of Human Milk: A Within-Subject Pilot Study

Background: Responsive feeding promotes optimal feeding patterns and growth trajectories. Breastfeeding is thought to facilitate responsive feeding, but research to date has been limited to comparing formula-feeding and breastfeeding dyads. Using a within-subject approach, we aimed to assess maternal responsiveness to infant cues during two human milk feeding sessions differing by feeding modality (breastfeeding versus bottle feeding). Materials and Methods: Nine mother-infant dyads (infants ≤6 months) were recruited from the Halifax Regional Municipality, Nova Scotia, from April to May 2018. Two human milk-feeding sessions, directly from the breast and from a bottle, were video-recorded in participants' homes, then scored using the validated Nursing Child Assessment Satellite Training (NCAST) Caregiver/Parent-Child Interaction Feeding Scale. The second half of feeding sessions were coded for infant satiation cues. Results: All women earned a college degree or higher, and were partnered. Mothers were aged mean ± standard deviation 33.2 ± 4.0 years; infants were 14.6 ± 6.9 weeks old and six (67%) were female. Mothers were more sensitive to infant cues during breastfeeding (NCAST Maternal Sensitivity to Cues sub-scale score, 15.0 ± 1.0) than bottle feeding (13.4 ± 1.6; p = 0.016). There was a significantly longer latency from feeding session midpoint to the first satiation cue during breastfeeding (minutes:seconds; 3:00 ± 1:53 versus 0:45 ± 1:18 bottle feeding, p = 0.038). There was no difference in the number of infant cues by feeding modality. Conclusions: Despite the small sample with high socioeconomic status, this pilot study highlights differences in maternal responsiveness to infant cues by feeding modality with human milk, which warrants further investigation.

Exploring Correlates of Infant Clarity of Cues During Early Feeding Interactions

BACKGROUND

Recommendations aimed at reducing infants' risk for rapid weight gain primarily focus on promoting caregivers' use of responsive feeding practices and styles. These recommendations are grounded in the belief that infants will effectively signal hunger and satiation to their caregivers. To date, few studies have explored how variability in infants' communication of hunger and satiation may contribute to feeding interactions.

OBJECTIVE

Our aim was to explore variability in, and correlates of, infant clarity of cues during feeding interactions.

DESIGN

This was a cross-sectional study.

PARTICIPANTS/SETTING

Mother-infant dyads (n=86) were video-recorded during a typical feeding interaction within laboratory-based settings in Philadelphia, PA and San Luis Obispo, CA between June 2013 and June 2017.

MAIN OUTCOME MEASURES

Trained raters later coded videos using the Nursing Child Assessment Parent-Child Interaction Feeding Scale's Infant Clarity of Cues and Maternal Sensitivity to Cues subscales. Infant weight was assessed and standardized to sex- and age-specific z scores. Mothers completed questionnaires related to family demographics, infant feeding history, feeding styles, and infant temperament and eating behaviors.

STATISTICAL ANALYSES PERFORMED

Linear models were used to test for associations between clarity of cues and breastfeeding vs formula-feeding, maternal sensitivity and responsiveness, and feeding and weight outcomes.

RESULTS

Infants were approximately 15.5 weeks of age and 53% were female. Clarity of cues was not associated with infant sex, age, temperament, or eating behaviors. Breastfed and formula-fed infants exhibited similar clarity of cues (P=0.0636). Greater clarity of cues for infants was associated with greater maternal sensitivity to cues (P=0.0011) and responsive feeding style (P=0.0464) for mothers. Lower clarity of cues was associated with greater weight-for-age z score change for formula-fed infants, but not breastfed infants.

CONCLUSIONS

Efforts to promote responsive feeding may need to also consider infant clarity of cues. Further research is needed to understand the implications of associations between infant communication and responsive feeding.

Effects of opaque, weighted bottles on maternal sensitivity and infant intake

Caregivers' abilities to assess how much is in the bottle may lead to encouragement of infant bottle emptying and overfeeding. The present study assessed whether use of opaque, weighted bottles (as compared with conventional, clear bottles) improves feeding outcomes. Mothers with infants <32 weeks of age (n = 76) were assessed on two separate days. Mothers fed their infants from an opaque, weighted bottle on 1 day and a clear bottle on the other; conditions were counterbalanced. Blinded raters certified in the Nursing Child Assessment Feeding Scale scored all videos to determine maternal sensitivity. Infant intake was assessed by weighing the bottle before and after each feeding, and feeding outcomes included infant intake (mL), intake per kilogram body weight (mL/kg), meal duration (min), and feed rate (mL/min). Mothers exhibited significantly greater sensitivity (p = 0.041), fed their infants fewer millilitres per kilogram body weight (p = 0.049), and fed their infants at a significantly slower rate (p = 0.009) when using opaque compared with clear bottles. Infant clarity of cues was a significant moderator of effects of bottle type on intake per kilogram body weight (p = 0.028): Infants who exhibited greater clarity of cues were fed less during the opaque versus clear conditions whereas infants who exhibited poorer clarity of cues were fed similar amounts during both conditions. Effects of bottle type were not moderated by bottle contents (expressed breast milk vs. formula). In sum, promotion of opaque, weighted bottles for infant feeding may be a pragmatic approach to improve the quality and outcome of bottle-feeding interactions.