Developmental Trajectories of Bottle-Feeding During Infancy and Their Association with Weight Gain

Awareness and Support of Responsive Bottle Feeding Among WIC Counselors and Caregivers: A Formative Qualitative Study

OBJECTIVE

To understand the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) counselor experiences discussing responsive bottle feeding during counseling and WIC participants' knowledge, understanding, and use of responsive bottle feeding.

METHODS

Qualitative descriptive, semistructured interviews with 23 participants (8 WIC counselors and 15 WIC participants) were conducted online via Zoom. The WIC counselors and mothers of WIC-enrolled bottle-fed infants were recruited through a network of WIC clinics in North Carolina. Interviews were recorded, transcribed, and collaboratively analyzed using content analysis.

RESULTS

The WIC participants received responsive infant feeding support from WIC counselors but often in the context of breastfeeding. WIC counselors provided valuable support for families but were challenged by limited training on responsive bottle feeding, balancing promoting breastfeeding with supporting mothers' feeding decisions, and time constraints.

CONCLUSIONS AND IMPLICATIONS

Findings provide preliminary support for the need to develop and pilot an intervention focused on promoting responsive feeding for parents of bottle-fed infants.

Comparison of the Effect of Direct Breastfeeding, Expressed Human Milk, and Infant Formula Feeding on Infant Weight Trajectories: A Systematic Review

Background: Formula and breastfeeding are known factors associated with infant weight trajectories. Evidence exploring the effect of expressed human milk feeding on infant weight in the community setting has not been well synthesized. Objectives: This systematic review examined (1) weight changes among infants fed expressed human milk and (2) differences in weight change between infants fed expressed human milk and infants fed at the breast or infant formula via bottle. Methods: A comprehensive search of the literature was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The quality of each study was appraised using the Joanna Briggs Critical Appraisal Tools. Results: A total of six studies met the eligibility criteria and included a total of 5,152 infants. The within-subject analysis identified only 31 infants strictly or predominantly fed expressed human milk. The between-subject analysis comparing expressed human milk feeding to the available comparison groups (formula-fed or direct at the breastfed) revealed that higher weight gains were observed in the weight trajectories among infants in the bottle or formula-fed conditions in four of the six included studies. Conclusions: Findings from the few studies included in this review found a difference in the infant weight gain patterns among expressed human milk-fed infants when compared with their respective feeding groups (directly breastfed or formula-fed). Further research is needed to corroborate these findings and elucidate the clinical significance of the differences in weight gain patterns observed across infant feeding groups.

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.

Co-Design of a Reusable Learning Object (RLO) to Address Caregiver Responsive Infant Feeding Behaviours (CRIB) to Prevent Childhood Obesity: A Mixed-Method Protocol

Responsive infant feeding is a key strategy for childhood obesity prevention. Responsive feeding involves caregivers responding to infant hunger and satiety cues in a timely and developmentally appropriate manner. There is a dearth of evidence-based information and guidance for caregivers on how to responsively feed their infants. The aim of this research is to co-design a Reusable Learning Object (RLO) and guidance infographic to improve caregiver awareness, understanding and use of responsive infant feeding behaviours. The Capability, Opportunity, Motivation and Behaviour (COM-B) model of behaviour change and the Aim, Storyboarding, Populate specification, Implement media, Review and release prototype, and Evaluate (ASPIRE) approach for digital intervention co-design will be utilised. Four co-design workshops with caregivers of infants and healthcare professionals (HCPs) will determine priority RLO content. Content analysis will enable RLO development and process reporting. Formative and summative surveys will be conducted to evaluate the usability of the RLO, its impact on caregivers and its potential implementation into NHS care pathways. The output will be a RLO on responsive feeding for caregivers and an infographic for HCPs/support workers which will contribute to a future obesity prevention intervention. The findings will be disseminated to stakeholders and submitted for publication in a peer-reviewed journal.

Breastfeeding duration is associated with higher adiposity at 6-8 months of age

Breastfeeding (BF) has been identified as a protective factor against childhood obesity. However, evidence of the association between BF duration and adiposity remains inconclusive. Few studies have been conducted among Southeast Asian infants that have measured body composition during infancy using the gold standard stable isotope method. This study aimed to evaluate the association between BF duration and body composition during infancy. Healthy full-term Thai infants aged 6-8 months (n = 60) receiving exclusive or predominant BF for at least 3 months were recruited. Skinfold thickness (SFT) was measured by well-trained investigators. Body composition was assessed by the deuterium dilution technique. Infants with longer BF duration (>6 months; mean 7.5 ± 0.5 months, n = 29) had a higher subscapular SFT z-score than those with shorter BF duration (≤6 months; mean 5.3± 0.9 months, n = 31) by 0.48 (95% confidence interval [CI]: 0.01-0.94). After adjustment for age and sex, BF duration and age at introduction of complementary feeding (CF) were positively associated with fat mass and fat mass index at 6-8 months. One month increase in BF duration and CF age was associated with a 0.37 (95% CI: 0.05, 0.69) kg/m² and 0.76 (95% CI: 0.18, 1.34) kg/m² increase in the fat mass index, respectively. After adjusting for infant body mass index (BMI) during the earlier infancy period, the strength of the association was attenuated. This finding may reflect reverse causality where infants with lower BMI received formula or CF earlier. A longitudinal study with follow-up into childhood is warranted to confirm the effects of BF on adiposity in infancy and childhood.

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.

"Painful, yet Beautiful, Moments": Pathways Through Infant Feeding and Dynamic Conceptions of Breastfeeding Success

What is breastfeeding "success"? In this article, we challenge the traditional biomedical definition, instead centering visions of success described by breastfeeding mothers themselves. Using semi-structured interviews, quantitative surveys, and written narratives of 38 first-time mothers in the United States, we describe five common pathways through the first-year postpartum, a taxonomic distinction far more complex than a success-failure dichotomy: sustained breastfeeding, exclusive pumping, combination feeding, rapid weaning, and grinding back to exclusivity. We also explore the myriad ways in which mothers define and experience breastfeeding success, and in the process uncover the ways that cultural narratives-especially intensive mothering-color those experiences. Finally, we discuss how these experiences are shaped by infant feeding pathway. In doing so, we discover nuance that has gone unexplored in the breastfeeding literature. These findings have implications for supporting, promoting, and protecting breastfeeding in the United States and other high-income countries.

Artificial Neural Network for Identification of Infant Feeding Tracking Using the Smart Bottle System

In this work, we present the results of a comparison of simple artificial neural network (FFNN) designs intended to identify infant bottle-feeding events and appropriate feeding volume recording intervals using accelerometer data recorded from a custom designed "Smart Bottle" system. To properly identify and distinguish these events with an accuracy of 99.8%, while accommodating the constraints of the deployment environment, two concurrent FFNNs were implemented.

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.

Infant feeding and growth trajectories in early childhood: the application and comparison of two longitudinal modelling approaches

BACKGROUND/OBJECTIVES

The role of infant feeding practices in longitudinal growth trajectories in children remains equivocal. This study utilised two longitudinal approaches to examine the associations of infant feeding mode (breastfeeding, mixed feeding, formula feeding), breastfeeding duration, and the timing of solid foods introduction with body mass index (BMI) z-score in early childhood.

SUBJECTS/METHODS

Secondary analyses of data from the Healthy Beginnings Trial were conducted. Infant feeding practices were reported by mothers at 6, 12, and 24 months of child age. Child weight and length were measured at birth, 12, 24, 42, and 60 months. Two longitudinal approaches: linear spline multilevel model (LSMM) and group-based trajectory modelling (GBTM) were used to describe BMI z-score trajectories and assess its associations with infant feeding practices.

RESULTS

The LSMM approach demonstrated that the breastfeeding group showed lower BMI z-scores from ages 12 to 60 months than the mixed feeding and formula feeding groups. Children who were breastfed for ≥ 6 versus < 6 months exhibited a lower BMI z-score trajectory from ages 12 to 60 months. Results from the GBTM approach revealed that the mixed feeding (OR: 1.83, 95%CI 1.04, 3.21) and the formula feeding group (OR: 2.00, 95%CI 0.67, 5.92) showed a tendency for higher odds of following the "High BMIz" trajectory than the breastfeeding group. Breastfeeding duration ≥6 versus < 6 months was linked with lower odds of following the "High BMIz" trajectory (OR 0.65, 95%CI 0.43, 0.98). Both approaches revealed no evidence of an association between the timing of solid foods introduction and BMI z-score trajectory.

CONCLUSIONS

The two longitudinal approaches revealed similar findings that infant feeding mode and breastfeeding duration, but not the timing of solid foods introduction, were associated with BMI z-score trajectory in early childhood. The findings provide robust longitudinal evidence to encourage and support extended breastfeeding for childhood obesity prevention.

A cross-sectional analysis of infant-driven and traditional feeding outcomes for neonatal intensive care unit infants

OBJECTIVE

The goal of this study was to assess the impact of infant-driven feeding (IDF) compared to traditional feeding protocols in promoting earlier successful feeding outcomes.

STUDY DESIGN

We performed a cross-sectional analysis of infants admitted to a level three neonatal intensive care unit (NICU) over a 2-year period. We compared infants fed with the traditional protocol to those under the IDF protocol.

RESULTS

Infants in the IDF group were younger at first feed (p < 0.001). There was no difference in age at nasogastric (NG) tube removal or at discharge, length of stay, or percentage breastfeeding at discharge. There were no differences in outcomes within two subgroups born at <35 and <32 weeks gestation, respectively.

CONCLUSION

The IDF program led to earlier initiation of oral feeding. However, this did not lead to earlier NG tube removal or discharge, a shorter length of stay, or increase in the rates of breastfeeding.

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.

Mother-infant interactions and infant intake during breastfeeding versus bottle-feeding expressed breast milk

Bottle‐fed infants are at higher risk for rapid weight gain compared with breastfed infants. Few studies have attempted to disentangle effects of feeding mode, milk composition and relevant covariates on feeding interactions and outcomes. The objective of the present study was to compare effects of breastfeeding directly at the breast versus bottle‐feeding expressed breast milk on feeding interactions. Mothers with <6‐month‐old infants (n = 47) participated in two counterbalanced, feeding observations. Mothers breastfed their infants directly from the breast during one visit (breast condition) and bottle‐fed their infants expressed breast milk during the other (bottle condition). Masked raters later coded videos using the Nursing Child Assessment Parent–Child Interaction Feeding Scale. Infant intake was assessed. Mothers self‐reported sociodemographic characteristics, infant feeding patterns (i.e. percentage of daily feedings from bottles) and level of pressuring feeding style. Mother and infant behaviours were similar during breast and bottle conditions. Percent bottle‐feeding moderated effects of condition on intake (P = 0.032): greater percent bottle‐feeding predicted greater intake during the bottle compared with breast condition. Effects of feeding mode were not moderated by parity or pressuring feeding style, but, regardless of condition, multiparous mothers fed their infants more than primiparous mothers (P = 0.028), and pressuring feeding style was positively associated with infant intake (P = 0.045). Findings from the present study do not support the hypothesis that feeding mode directly impacts dyadic interaction for predominantly breastfeeding mothers and infants, but rather suggest between‐subject differences in feeding experiences and styles predict feeding outcomes for this population.

Associations between Bottle-Feeding during Infancy and Obesity at Age 6 Years Are Mediated by Greater Infancy Weight Gain

Objective: To explore whether the association between bottle-feeding during the first year and childhood obesity at age 6 years is mediated by change in weight-for-age z-score (ΔWAZ) during infancy. Methods: Participants were 1062 mother-child pairs who participated in the Infant Feeding Practices Study II and Year 6 Follow-Up. Mothers completed 1 prenatal questionnaire, 10 postpartum questionnaires during the first year, and 1 follow-up questionnaire at 6 years. Child weights were reported by mothers and used to determine ΔWAZ from birth to later infancy. Causal mediation analysis was used to determine the average direct effect of bottle-feeding on obesity at age 6 years and the average causal mediation effect of bottle-feeding through ΔWAZ. Results: Infants who experienced rapid increases in bottle-feeding frequency during the first 6 months had significantly greater ΔWAZ compared with infants who had consistently low bottle-feeding frequency until 12 months of age [β = 0.45, 95% confidence interval (CI) 0.11-0.80]. Significant predictors of obesity at age 6 years were larger birth weight [adjusted odds ratio (AOR) = 4.27, 95% CI 2.42-7.64] and larger ΔWAZ (AOR = 1.59, 95% CI 1.29-1.98). An indirect effect of bottle-feeding, mediated via ΔWAZ, accounted for 59% of the total effect of bottle-feeding on obesity at age 6 years. Conclusions: Rapid increases in bottle use during the first 6 months postpartum predicted greater risk for obesity at age 6 years via an indirect mediation effect of larger ΔWAZ from birth to later infancy.

Modifications to Infant Formula Instructions Improve the Accuracy of Formula Dispensing

Readability of infant formula preparation instructions is universally poor, which may result in inaccurate infant feeding. Given that inaccurate formula dispensing can lead to altered infant growth and increased adiposity, there is an increased need for easy to follow instructions for formula preparation. We hypothesize that altering infant formula instruction labels using feedback from iterative focus groups will improve the preparation accuracy of powdered infant formula in a randomized controlled trial. Participants were recruited from the community, 18 years of age or older, willing to disclose demographic information for focus group matching, and willing to participate freely in the first (n = 21) or second (n = 150) phase of the study. In the second phase, participants were randomized to use the standard manufacturer instructions or to use the modified instructions created in the first phase. Accuracy was defined as the percent error between manufacturer-intended powder formula quantity and the amount dispensed by the participant. Participants who were assigned to the modified instructions were able to dispense the powdered formula more accurately than participants who used the standard manufacturer instructions (−0.67 ± 0.76 vs. −4.66 ± 0.74% error; p < 0.0001). Accuracy in powdered formula dispensing was influenced by bottle size (p = 0.02) but not by body mass index (p = 0.17), education level (p = 0.75), income (p = 0.7), age (p = 0.89) or caregiver status (p = 0.18). Percent error of water measurement was not different between the groups (standard: −1.4 ± 0.6 vs. modified: 0.7 ± 0.6%; p = 0.38). Thus, caloric density was more accurate in the modified instructions group compared to the standard manufacturer instructions group (−0.3 ± 0.6 vs.−2.9 ± 0.9%; p = 0.03). Infant formula label modifications using focus group feedback increased infant formula preparation accuracy.

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.

Predictors of Resilience Among Infants at Risk for Rapid Weight Gain

OBJECTIVE

The study objective was to investigate factors associated with resilience to rapid weight gain (RWG) among predominantly bottle-fed infants.

METHODS

Data came from 1,353 mothers who participated in the Infant Feeding Practices Study 2. Mothers completed a prenatal questionnaire and monthly surveys of infant feeding and growth between birth and 12 months. Infants were classified as resilient if they were predominantly bottle fed but did not exhibit RWG between birth and the latter half of infancy (≥ +0.67 change in weight-for-age z score).

RESULTS

Thirty-five percent of the sample (n = 467) was predominantly bottle fed but did not exhibit RWG ("Resilient"), 17% (n = 228) was predominantly bottle fed and exhibited RWG ("Not Resilient"), and 49% (n = 658) was not predominantly bottle fed ("Low Risk"). Significant predictors of resilience to RWG were greater gestational age (P = 0.042) and weight (P < 0.001) at birth, lower frequency of adding cereal to the bottle (P = 0.022), lower frequency of infant-led bottle-emptying (P = 0.047), and greater frequency of maternal encouragement of bottle-emptying (P = 0.002).

CONCLUSIONS

Associations between bottle-feeding and RWG may be moderated by infant characteristics and maternal feeding practices. The present study highlighted several characteristics of predominantly bottle-fed infants who were resilient to RWG, but further research is needed to identify a broader array of key targets for future intervention efforts.

Latent trajectories of infant breast milk consumption in the United States

Patterns of breastfeeding over time are not currently well understood. Limited qualitative and quantitative evidence suggests that there may be latent subgroups of mothers in the United States following very different trajectories of breast milk provision for their infants. This study used a quantitative modelling method (group-based trajectory modelling) to identify and describe these subgroups. Using data from the Infant Feeding Practices Study II (n = 3,023), the authors identified four distinct trajectories of breastfeeding intensity, each of which included a substantial subset of the total sample. A model with four groups fit the data well by objective and conceptual standards. Bivariate associations were analysed, and significant difference between trajectory group membership was found on an array of maternal and family determinants, including maternal demographics, hospital experience, and psychosocial resources, as well as on postweaning perceptions. These associations were used to create group profiles for each subgroup. Controlling for sociodemographic covariates, we also found that trajectory membership was significantly associated with several health outcomes for the target child 6 years later, including certain infections, picky eating, and health care utilization; trajectory group membership was also associated with maternal breastfeeding of subsequent children and maternal body mass index (BMI) at Year 6. Child BMI z-score and maternal breast cancer diagnosis were not significantly different across trajectory groups after accounting for confounding covariates, nor was time missed from school for the target child. Though exploratory, the initial identification and description of these four subgroups suggest future directions using breastfeeding trajectory methods, with potential implications for measurement, intervention development, and targeting.

Infant formula feeding practices associated with rapid weight gain: A systematic review

Excess or rapid weight gain during the first 2 years of life is associated with an increased risk of later childhood and adult overweight and obesity. When compared with breastfed infants, formula fed infants are more likely to experience excess or rapid weight gain, and this increased risk in formula fed infant populations may be due to a number of different mechanisms. These mechanisms include the nutrient composition of the formula and the way formula is prepared and provided to infants. This systematic literature review examines the association between formula feeding practice and excess or rapid weight gain. This review explores these different mechanisms and provides practical recommendations for best practice formula feeding to reduce rapid weight gain. Eighteen studies are included in this review. The findings are complicated by the challenges in study design and accuracy of measurements. Nevertheless, there are some potential recommendations for best practice formula feeding that may reduce excess or rapid weight gain, such as providing formula with lower protein content, not adding cereals into bottles, not putting a baby to bed with a bottle, and not overfeeding formula. Although further well designed studies are required before more firm recommendations can be made.

An Ecological Momentary Assessment of Primiparous Women's Breastfeeding Behavior and Problems From Birth to 8 Weeks

BACKGROUND

Primiparous women are at risk for early, unintended breastfeeding reduction and cessation. Breastfeeding patterns that contribute to these outcomes require further exploration. Research aim: This study aimed to describe early, "real-time" breastfeeding behaviors and perceived problems of primiparous women.

METHODS

First-time mothers intending to exclusively breastfeed downloaded a commercial infant-feeding app during their postpartum hospitalization. Women logged feedings and their breastfeeding experiences, as they occurred, through 8 weeks postpartum. Additional feeding and background data were collected via electronic medical records and questionnaires administered at enrollment and 2 and 8 weeks postpartum. Summary statistics were compiled to examine weekly breastfeeding behaviors and problems.

RESULTS

In this sample of 61 primarily highly educated, White women committed to breastfeeding, 38% ( n = 23) used formula during the postpartum hospitalization and 68% ( n = 34) used formula at least once by 2 weeks. Nine women stopped breastfeeding during the study. Women using any formula in the hospital and those with less positive baseline attitudes toward breastfeeding were less likely to be exclusively breastfeeding at 2 and 8 weeks, respectively ( p < .05). There was a trend toward declining at-breast feeds and high rates of milk expression during the study. Breastfeeding problems peaked at Week 2, with 81% of women ( n = 39) endorsing at least one problem at that time. The most prevalent problems included perception of inadequate milk, pain, latching, and inefficient feeds.

CONCLUSION

Interventions to address suboptimal breastfeeding in primiparous women should consider the pervasiveness of early milk expression and in-hospital formula supplementation in this population, as well as the trajectory of common problems.