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

Abstract 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.

Breastfeeding guidelines and recommendations discuss strategies to assist the dyad if problems arise during the establishment and maintenance of breastfeeding (National Health & Medical Research Council, 2012). Topics covered in the guidelines and policies include positioning and attachment of the infant on the breast, mother's position, milk transfer and production, feeding a baby to their need, normal infant behaviour, and everyday problems (National Health & Medical Research Council, 2012; World Health Organization (WHO), 2017).
Bottle-feeding guidelines and recommendations, however, tend to focus on aspects of health and safety (National Health & Medical Research Council, 2012;WHO, 1981). Bottle-feeding advice concentrates on more procedural recommendations: cleaning and sterilizing of feeding equipment, correct preparation of formula, and the storage and transport of formula (United Nations Children's Fund (UNICEF) UK, 2015). Although these guidelines are indeed important, what appears to be lacking is the consideration of bottlefeeding as a holistic system and how to optimally feed infants when using a bottle.
Previous research indicates there are differences in the practice of breastfeeding and bottle-feeding and mothers' behaviours . Parents and health practitioners who support them are faced with a myriad of decisions in the application of bottle-feeding. This review considers the importance of infant positioning and attachment on the bottle, differences between bottles and teats, and the parent infant feeding interaction.
An integrative review of the empirical literature will investigate these aspects of bottle-feeding. General systems theory is the theoretical construct of the review, in recognition that bottle-feeding is a system of interdependent parts. Thus, no one aspect is independent.
The majority of research on the topic of bottle-feeding has investigated the various aspects. This review will consider these within the context of a holistic system and how to support optimal feeding when using a bottle.

| METHODS
This review aims to provide "a new way of thinking about …" (Torraco, 2016, p. 412), the act of bottle-feeding as an infantfeeding modality. An integrative literature review methodology is well-suited for this review as it is a form of research structured around existing literature that intends to answer a specific research question (Torraco, 2016). The scope of this review considers bottle-feeding as a system (Bertalanffy, 1972). The successful functioning of a system relies upon the contribution of interrelated parts (Broderick, 1993). Fundamental aspects of bottle-feeding include, how infants obtain milk from a bottle, how bottle-feeding equipment influences milk delivery to the infant, and how the infant's milk intake may be affected by parent-infant communication during bottle-feeding.
There are external influences within the environment that impact on bottle-feeding, society, culture, media, health services, family, and attitudes, and these variables lay outside the scope of this review. The review's focus is to deepen our understanding of the physiological and functional parts of the bottle-feeding act. The graphical representation in Figure 1 shows bottle-feeding as a system (diagram adapted from http://ric357.ru/ludwig-von-bertalanffygeneral-system-theory-78/).

| Inclusion criteria
Studies with a focus on healthy full-term infants under 6 months of age, fed via a bottle with either breast milk or formula, were eligible for inclusion. Infants under 6 months were the criterion considered appropriate because the maturation of an infant's oral-motor function, developmental changes, and primitive feeding reflexes (tongue thrust) disappear around 6 months when an infant starts solid feeding. Studies with a focus on the mechanics of how infants bottle-feed, the mechanics of bottles and teats as a milk delivery system, and the mother/carer's actions during the bottle-feeding interaction, were eligible. Sex and ethnicity of the bottle-feeding dyad was not a limiting factor for inclusion.

| Exclusion criteria
Studies that focused on preterm infants, breastfeeding outcomes only, infants over 6 months of age, bottle-feeding relating to specific medical conditions, and infants with ongoing medical issues, were excluded. These variables have the potential to affect an infant's oral-motor function, thus outside the scope of the review. Studies that investigated the mother's attitudes, experiences, and choice of feeding modality also did not align with the scope of the review.

Key messages
• While breastfeeding is a global priority, a significant number of infants are fed using a bottle.
• There is limited quality information for parents/caregivers and health professionals on the act of bottle-feeding.
• The anatomical actions used by healthy term infants are similar when breast or bottle-feeding.
• Teat flow rates affect an infant's sucking pattern and milk intake. There is significant variability within the brand and classification of the teat flow rate.
• The anatomical actions used by healthy term infants are similar when breast or bottle-feeding.
• Infants are interactive partners in the process of bottlefeeding.

| Search strategy
An initial search of the literature was conducted before October 2019 using the term bottle-feeding resulting in 12,075 articles. The databases searched include CINAHL, PsycINFO, Medline, ProQuest, and Scopus. MeSH terms, bottle-feeding, and infant, and anatomy, and physiology, and bottle-feeding equipment, and communication and cues, were then inserted in the search criteria to align with the scope of this review. Articles were limited to English, peerreviewed studies. The articles for review numbered 2,404, once duplicates were removed. The title and abstracts were scrutinized using the inclusion and exclusion criteria, 56 articles were selected.
A search of these articles' references was undertaken to reveal a further 13 relevant studies. A full-text screen was carried out on the 69 retrieved articles; of these, 38 articles did not meet the inclusion criteria. The final 31 articles are in this review. The PRI-SMA flowchart (Buck, 2019) illustrates the search process (refer to Figure 2).

| DATA ANALYSIS
The studies were grouped according to the fundamental aspects of bottle-feeding. Eight studies focused on the mechanics of how infants obtain milk from bottles. Thirteen studies focused on the characteristics of how bottles and teats affect milk delivery to the infant. Ten studies examined how communication and cues during the feeding interaction affect an infant's milk intake. The table of evidence presents a tabulation of the studies, refer to Table 1. Quality assessment and to reduce bias in the analysis of the studies, the Crowe Critical Appraisal Tool (CCAT) was used (Crowe, Sheppard, & Campbell, 2012). The CCAT tool, a validated method for appraising different research designs, provides a reliable and consistent method for reducing bias in the review. A study is broken down into eight categories, with each category given a score out of 5, a possible total of 40 (100%) for the entire study. These scores illustrate the strengths, reproducibility, replicability, and the weakness of the individual studies (Crowe, 2013). A consensus was obtained on the CCAT scores for 10 of the 31 studies by two of the authors to provide consistency and accuracy to the quality assessment process. The final CCAT scores are in Table 1.

| Study characteristics
As detailed in the table of evidence, there were nine countries represented. Two studies were a joint venture in the United Kingdom and Sweden, and Israel and the United Kingdom. The majority of research designs for the studies were quantitative, using longitudinal, crosssectional, observational, and descriptive data, with one exploratory ethological qualitative study. No systematic reviews met the inclusion criteria for this review. A comparison between bottle-feeding and breastfeeding results was a frequent occurrence. Most studies used convenience sampling consisting of small sample sizes, with the mother identified as the primary caregiver. Health facilities were the main settings for the studies that assessed infants in the first week of life, and the study design required the use of specific medical equipment. Ethical issues were generally lower on the CCAT because of the year the study was published or when ethics approval was not applicable.
F I G U R E 1 The theoretical construct of bottle-feeding as a system
The infant's tongue was identified as playing a significant role in milk transfer when breast-or bottle-feeding (Ardran et al., 1958;Weber et al., 1986). The studies that viewed an infant's feeding by either x-ray or ultrasound used different terminologies to characterize this tongue and jaw action (Ardran et al., 1958;Geddes et al., 2012 ;Weber et al., 1986). For example, in the seminal study by Ardran et al. (1958), the term "peristaltic" was used to describe the movement of the pharyngeal wall. Their summary discussed compression and squeezing of the teat by the tongue, along with suction, gravity, and teat hole size being factors influencing milk transfer when bottlefeeding (Ardran et al., 1958). Ultrasound studies used the same terms, peristaltic and piston-like, yet contradicted which term is applied to which feeding modality Weber et al., 1986). Breast-and bottle-feeding infants use " … a squeezing or stripping action … ," breastfeeding infants " … appeared to be rolling or peristaltic … ," and bottle-feeding infants used a " … piston-like or squeezing … ," action (Weber et al., 1986, p. 22). Geddes et al. (2012, p. 448) refer to the tongue action when breastfeeding as " … piston-like … " creating suction and an "… up and down movement rather than peristaltic …". The majority of the studies concluded that healthy term bottle-feeding infants use similar tongue and jaw movements compared with breastfeeding infants when obtaining milk during a feed (Ardran et al., 1958;Geddes et al., 2012;Goldfield et al., 2006;Nowak et al., 1994;Weber et al., 1986).
Several studies debated the primacy of suction and or compression in milk transfer when feeding; with suction being the main element proposed for how breastfeeding infants obtain milk and F I G U R E 2 PRISMA diagram bottle-feeding search results T A B L E 1 Forty mother-infant dyads with healthy term infants; 21 breastfeeding-12 males, nine females; 19 bottle-feeding-nine males, 10 females.
Observational study with the dyads being visited seven times from birth until the infant was 6 months of age. Feeding was videotaped, records made of feeding interaction, records of infant's milk intake over a 3-day period and birth weight. Mother and infant behavioural categories were developed to operationalize the concept of who controls the start, activities during the feed and the end of a feed.
Suggestion that infants lower birth weight affects mothers feeding style.
Association between pressure to feed a smaller infant and the less they consumed, longer the feed. Advice within hospitals may be a reason for mother's pressuring behaviour. Infant controls the feed when breastfeeding-regulates milk intake.
Golen and Ventura (2015) USA Explored whether "mindless feeding," or maternal distraction during bottle-feeding, is associated with greater infant formula/milk intakes and lower maternal sensitivity to infant cues.
28 infants less than 24 weeks of age.
Video recording of feeds assessed by Nursing Child Assessment Feeding Scale.
Mother's distraction during bottle-feeding coupled with infant characteristics affects milk intake.
Larger milk intake is associated with infant's age; mother's sensitivity to infant cues affected by her distraction; infant's lower self-regulation and higher emotional reactivity is a factor. Whitfield and Ventura (2019) Canada Assess maternal responsiveness to infant cues during milk feeding differing by feeding modality. Also, to quantify infant satiation cues by feeding mode.
Nine mother-infant dyads, Infants less than 6 months of age. Breast milk used in bottles.
Exploratory cross-sectional (pilot) study. NCAST in-home, two sessions video recorded, one breastfeeding and one bottle-feeding, coding software for satiation cues. Questionnaires demographics Mothers were more sensitivity to infant cues when breastfeeding than when bottle-feeding their EBM. Postulate infants have an active role when breastfeeding and not when bottle-feeding. No difference in number of infant's satiation cues or activity by feeding mode. Limitations discussed; recommendations made.
132 bottle-feeding dyads and, 58 breastfeeding dyads <7 days in post-natal ward. Home visits at 1 and 2 months Exploratory ethological study. Food diaries over 3 days, completed on day 3, 4, and 5 days of age. Video recording of feeding sessions and recording of behaviour categories during a feed as per Crow et al. (1980). Rate changes of sucking and diurnal variations in milk intake at 1 week, 1 and 2 months were documented. Description of behaviour categories used.
Patterns and behaviours of breastfed infants differ from bottle-feed infants. Postulate, breastfeeding infants control -learn to regulate hunger and milk intake depending upon time between feeds and determine the pace and duration of the feed. Breastfeeding mother's play a more passive role in an infant's milk intake. Whereas, mothers have more control of bottle-feeding infant's intake. Bottle-fed infants have regular feed times and milk intake regardless of time between feeds. CCAT score: 90% Prelim,5;Intro,4;Design,4;Sampling,4;Data collection,4;Ethics,4;Results,5;Discussion,5. compression as the main element for bottle-feeding infants Sakalidis et al., 2012;Weber et al., 1986). Both Geddes et al. (2012) and Sakalidis et al. (2012) used an experimental teat that only released milk by suction, which demonstrated that suction was responsible for milk transfer, not compression. The infants who participated in both studies were breastfeeding and had previously supplemented their feeds with a bottle. It was acknowledged that bottlefeeding term infants do create suction and sequentially use teat compression (Weber et al., 1986), with gravity being a factor in the transfer of milk (Ardran et al., 1958). Ardran et al.'s (1958)  Coordination of suck-swallow-breath (SSB) patterns were also viewed as an essential element for successful infant feeding (da Costa et al., 2010;Moral et al., 2010;Qureshi et al., 2002;Sakalidis et al., 2012;Taki et al., 2010;Weber et al., 1986). Breast-and bottlefeeding infants' SSB patterns changed because of an infant's age, with the newborn's reflexive SSB pattern of one or more sucks per swallow to longer sucking bursts as the infant matured (Qureshi et al., 2002;Weber et al., 1986). Therefore, the change in SSB pattern differs depending upon which part of the feed is observed (Taki et al., 2010).
Overall, there seem to be minimal differences in oxygen saturation and SSB patterns between healthy term breast-and bottle-feeding infants (Fadavi et al., 1997;Goldfield et al., 2006;Sakalidis et al., 2012;Weber et al., 1986). The studies determined that feeding modality does not necessarily influence SSB patterns.
A change in an infant's SSB when breast-or bottle-feeding was associated with milk availability and milk flow rate (Qureshi et al., 2002;Sakalidis et al., 2012;Weber et al., 1986). It was suggested that bottle-feeding infant's sucking patterns are dependent upon teat and bottle characteristics (da Costa et al., 2010). Taking into consideration how SSB patterns change during a feed, and how bottles/teats influence milk flow, the findings in the study by da Costa et al. (2010) requires reflection. This study only assessed the first 2 min of an infant feeding and found that bottle-feeding infants had more arrhythmical sucking (AS) patterns compared with breastfeeding infants. When examining the characteristics of the infants with AS patterns, they were consuming high quantities of milk, had low birth weight, needed medical attention in the first couple of days of life, and were choking and leaking milk when feeding.
Milk intake and bottle sizes were investigated with larger sized bottles being associated with an infant consuming an extra 15 kcal/kg of milk (Wood et al., 2016). It was discussed other contributing factors as possibly affecting the use of larger bottles were an infant's growth, responsiveness to infant's feeding cues, and parental feeding style (Wood et al., 2016). However, Ventura and Golen's (2015) pilot study examining contextual cues when bottle-feeding found no relationship to bottle size and milk intake. Their results implicate both the visual and weight of milk in the bottle, regardless of parenting feeding style, affecting an infant's milk intake.
Studies have reported an infant's milk intake is influenced by teat characteristics (Ardran et al., 1958;Geddes et al., 2012;Mathew, 1990;Nowak et al., 1994;Nowak, Smith, & Erenberg, 1995;Pados et al., 2019;Salisbury, 1975), with milk flow rate to an infant affected by the teat material, shape, hole size, its rigidity and compressibility, the bottle material, and the rigidity and pressure used by the infant (Ardran et al., 1958;da Costa et al., 2010;Goldfield et al., 2006;Mathew, 1990;Nowak et al., 1994;Salisbury, 1975;Walden & Prendergast, 2000). Studies that examined commercially available teats found a wide variation in flow rate between brands, within the same brands and the same labelled teat flow rate (Mathew, 1988;Pados et al., 2016;Pados et al., 2019;Pados, Park, Thoyre, Estrem, & Nix, 2015). The conclusion being the company's labelling and terminology on teat flow rates were confusing and it was challenging to compare flow rates between brands (Pados et al., 2016). Two studies using different methods examined flow rates of cross-cut teats (Mathew, 1988;Walden & Prendergast, 2000). In the study by Mathew (1988) suction was applied to the cross-cut teat resulting in no flow. However, Walden and Prendergast (2000) found the cross-cut teat had a faster flow rate during a compression test compared with single hole teats. This study did describe teat characteristics of material and hole size. Pados et al. (2019) hypothesized that the variability of flow rates within the same teat range is possibly a reason for infant feeding diffi- culties. It appears that if milk flow is continuous or too fast, this can affect sucking patterns, with some infants unable to adjust their SSB patterns, causing feeding difficulties (Pados et al., 2015). For instance, the faster a teat flows equates to a larger volume delivered, the infant sucks less, with longer pauses between sucks to allow for swallowing and breathing. The consequences of a fast teat flow rate can manifest as breathing anomalies, drooling, and the possibility of aspiration of milk (Pados et al., 2016). Interestingly, commercial enterprise funded several studies; refer to Table 1.
A common weakness within the studies was a lack of description of teat characteristics. Only three studies provided information on the teat material used: latex/rubber and silicone (Moral et al., 2010;Walden & Prendergast, 2000;Weber et al., 1986). The teat flow rate was described in studies as like breastfeeding, medium flow, or the same flow (Fadavi et al., 1997;Moral et al., 2010;Sakalidis et al., 2012).
Teats were named either by brand or shape, with little or no detail given on their characteristics (Fadavi et al., 1997;Mathew, 1988;Moral et al., 2010;Nowak et al., 1995;Taki et al., 2010). It is unfortunate that because of teat characteristics, particularly the teat flow rate, discussed in most studies as affecting an infant's sucking and milk intake. The information on the teat flow rate as being inconsistent and too fast may influence some studys' conclusions.

| Parent-infant communication and cues during the feeding interaction
An infant's milk intake during feeding has a strong association to the interaction between the infant and parent/caregiver Shloim, Vereijken, Blundell, & Hetherington, 2017;Ventura & Mennella, 2017;Ventura, Sheeper, & Levy, 2019;. Rybski, Almli, Gisel, Powers, and Maurer (1984) found that a mother's interactions did not change over 24 hr, nor did they affect an infant's milk intake. However, the methodology of this study could be a factor for this finding. Bottle-feeds were scheduled and observed in a hospital setting, infants were bottle-fed in a bassinet, mothers were instructed on how to feed their infant and only held their infant to burp them.
Other studies explored bottle-feeding mother's interactions and linked her feeding style to an infant's milk intake Ventura & Hernandez, 2019;Ventura & Mennella, 2017). There was an agreement in these studies that when a mother has a pressuring feeding style, the infant is encouraged to consume more milk, and with a restrictive feeding style, the infant has lower milk intake. Mothers with either a pressuring or restrictive feeding style were found to be more responsive to their infant's cues when they could not see or feel the amount of milk in a bottle Ventura & Hernandez, 2019). If the mother is distracted during the feeding interaction, she is less sensitive and can miss the infant's cues, which can contribute to under or overfeeding of the infant .
Studies that explored maternal responsiveness and infant feeding cues found that bottle-feeding infants actively engage in and reciprocate responses of the mother allowing the infant to be an active participant in the feeding interaction Ventura & Mennella, 2017). However, breastfeeding infants were identified by Shloim et al. (2017) as displaying more cues of hunger and satiety than bottle-feeding infants. Suggesting this is because of the infant being an active participant when breastfeeding and passive when bottlefeeding. Whitfield and Ventura (2019) explored infant cues with the number of cues found to be similar for breast-and bottle-feeding. The mother's responsiveness to her infant cues was different when comparing her breast-and bottle-feeding interactions.
The methodology was a possible reason for the discrepancy between these studies. Ventura and Mennella (2017) Shloim et al. (2017) was the only study to explore infant communication without assessing the mother's response, possibly affecting her infant's cues during the feeding interaction. The authors cited the "Nursing Child Assessment Teaching Scale" as their basis for defining engagement and disengagement cues for hunger and satiety. They identified 22 out of the 83 feeding cues to use for data collection during the feeding interaction (Shloim et al., 2017, p. 76).
The feeding interaction was also considered to be influenced by infant characteristics, possibly affecting milk intake Ventura & Mennella, 2017;Wright et al., 1980). Infants with low regulation and surgency may not be clear in communicating their needs . Crow et al. (1980) suggest an association between bottle-feeding infants who had a low birth weight and the mothers' control over the feed. This issue of who controls the feed, mother or infant, is likely to affect an infant's ability to self-regulate their milk intake Wright et al., 1980).
A breastfeeding infant has control over starting and stopping feeding and learns to self-regulate their intake. Self-regulation of daily feeding patterns by the breastfeeding infant was not the case with bottle-feeding infants . Bottle-feeding infants usually are given the same volume of milk regardless of the time of day or time between feeds . The bottle-feeding mother was viewed as having the control over the amount in the bottle, starting and stopping feeding, probably impacting on the infant's learning to self-regulate Whitfield & Ventura, 2019).

| DISCUSSION
This review has examined 31 studies that have provided insight and information on the fundamental aspects of the mechanics of how infants obtain milk from bottles, the characteristics of bottles and teats affecting an infant's milk intake, and parent infant communication during the feeding interaction. When these parts are viewed in isolation, the utility of the information is not being used to its full potential. Looking at this information from a systems perspective, the understanding of the contribution and connection of the parts is a necessity (Bertalanffy, 1972).
Bottle-feeding as a system requires the infant, the parent/carer, and the bottle-feeding equipment to contribute to the process. The connections within and between these parts impact the feeding outcome. The infant's contribution to feeding relies upon their maturity and development of their oral feeding skills (Lau, 2016). The infant's oral feeding skills can be supported by the positioning of both infant and bottle during a feed (Kassing, 2002;Ross & Fuhrman, 2015). Kassing (2002) suggests for the infant to control milk flow, they need to be in an upright position with the bottle held horizontally. With the infant's characteristics of age, weight, and temperament influencing their success at communicating their needs during a feed Kielbratowska, Kazmierczak, Michalek, & Preis, 2015).
Parent/carer response to their infant's needs during feeding requires an understanding of their infant's communication. However, a recent systematic review of infant feeding interventions discussed limited evidence on parent/caregiver knowledge concerning responsive feeding practices (Matvienko-Sikar et al., 2019). Responsive feeding has been suggested as a learned behaviour between the dyad and is a reciprocal activity (Appleton et al., 2018;Oxford, & Findlay, D. (Eds.)., 2015; Ventura, 2018). Global infant feeding guidelines now advocate responsive feeding as a strategy to address milk intake and possible long-term effects of over-feeding (United Nations Children's Fund (UNICEF) UK, 2016), with milk delivery via bottles and teats linked to milk intake.
Bottle-feeding equipment has evolved in design because of the availability of new materials and research on how infants bottle-feed (Mathew, 1991;Pados et al., 2019;Ventura, 2018). However, commercial enterprise governs the information on bottle and teat characteristics, and there is no required standard to adhere to in the marketing nor labelling of these products (Dowling & Tycon, 2010;Pados et al., 2016). There are significant inconsistencies between the labelling of teats and actual performance (Pados et al., 2019), leaving parents and the health professionals that support them in a quandary when making decisions on appropriate bottle-feeding equipment.
The integration of the above information will allow strategies to optimize outcomes for both infants and families. For example, information to parent/carers on responsive feeding, how to maximize an infant's oral feeding skills, and the bottle-feeding technique suggested by Kassing (2002), could be a strategy to offset the variability of teat flow rates; the role of gravity, enabling an infant's to control their milk intake (self-regulation); and parental responsiveness during the feeding interaction.
Optimal bottle-feeding relies upon parents and health professionals' understanding of how infants obtain milk, how to use their oral feeding skills, how they attach on the bottle, how to position the infant and bottle, characteristics of the bottle-feeding equipment, and responsive feeding practices. By redefining the act of bottle-feeding as a holistic system, the interrelationship of these parts will be recognized along with the reciprocal nature of bottle-feeding; refer to F I G U R E 3 Model of the reconceptualization of the act of bottlefeeding as a system

| FUTURE RESEARCH
An understanding of the connection and relationship of these parts will foster the development of possible strategies to assist health professionals when supporting families who choose to use bottles to feed their infant. This review has identified a need for feeding behaviours of men and other carers to be explored, as well as the investigation of the parents'/carers' understanding of responsive feeding practices, ultimately providing a more holistic picture of this phenomena to guide further research and practice.

| LIMITATIONS
Only published peer-reviewed studies were considered, with other forms of related literature not included, possibly affecting the findings.
The heterogeneity of the articles reviewed presents challenges when synthesizing and generalizing findings.

| CONCLUSIONS
Systems theory is a unique approach to consider the act of bottlefeeding, and it is evident that this act is a complex process that is dependent on many variables working together. When one part is out of sync, it will impact on the other parts of the system influencing the outcome. Before strategies to assist the bottle-feeding dyad can be developed, investigation of parents' and health professionals' knowledge and understanding on the parts within the act of bottle-feeding needs to occur.