Today’s post is the second of three posts on Babywearing Research from Steffany Kerr, a Master Babywearing Educator with Babywearing International of O’ahu. Steffany has a research focus of examining babywearing instruction methods with high risk populations and babywearing instruction as a social welfare intervention.
In Part 1 of this series, I discussed some common misconceptions about babywearing research and touched briefly on some of the resources that are currently available. Now, I will go into more detail about relevant sources and the extent to which we can draw from research within related disciplines. This is NOT a thorough academic literature review; other professionals in the industry are currently undertaking that project. I will not provide an in depth and expansive analysis of all relevant studies on each topic, nor will I address every possible research question. My intentions with this piece are to highlight information from related studies that may be useful, while noting the limitations of non-babywearing specific research. Some of the topics discussed will elicit a contentious response as they are hot topics within the industry. I will not be making any assertions about best practices in this article. My hope is to equip babywearers and babywearing educators with the capacity to look at the available research through the lense of a researcher, to gain insight on what we have to build from, and to identify what gaps we need to address.
As an industry, we do have a fair amount of information available to us via research within related disciplines regarding hip development and hip health concepts. The International Hip Dysplasia Institute is one source that is commonly referenced in discussions about babywearing positioning. The IDHI Educational Statement asserts that wearing a baby in a carrier that does not offer optimal hip support or in a way that places the legs together “may contribute to Hip Dysplasia.” This sentiment is often relayed telephone style throughout the babywearing community, often with the intent to communicate certain positions or carrier types are unsafe and can cause Hip Dysplasia. There is NO DATA to support this conclusion. Studies have not been conducted and this conclusion is not at all supported by research. Sheffield Sling Surgery’s blog article Healthy Hips-Busting Some Myths addresses this topic with a brief review of relevant studies, and leads the reader to draw conclusions about positioning best practices by correlating hip dysplasia incidents to traditional babywearing practices and positioning. Unfortunately, as the research community often reminds its students, correlation does not imply causation. While it might seem like these related studies may be useful sources from which to draw conclusions about positioning best practices and the prevention of hip issues, the data only provides loose correlations. Studies controlling for specific carrying positions and/or using specific carrying devices in any statistically significant sample have yet to be conducted, meaning that we still lack data to support the notion that certain carriers or positions can cause or prevent hip issues.
A study conducted by Bracken, Tran, and Ditchfield (2012) highlights the challenges of drawing concrete conclusions from current hip dysplasia studies: “Developmental dysplasia of the hip (DDH) is a poorly understood entity, comprising a spectrum of abnormalities which, at one end, overlap with normal hip maturation. The deﬁnition of DDH is variable, which affects the published incidence and makes comparison between various studies difficult.” (p.963) Not only do we lack babywearing specific research regarding hip disorders, but we also lack any concrete data about the effect of using specific types of baby carriers with infants diagnosed with any of the spectrum of hip disorders that are often lumped into a Hip Dysplasia diagnosis. This article also states “Two small randomised trials have shown that stable hips with mild dysplasia on US (ultrasound) can be observed safely for 6 weeks, prior to initiating treatment, with no adverse effect on outcome,” (p. 968) which begs the question of how this finding could be applied to studies that clarify how babywearing might be best applied as an intervention during this “wait and see” timeframe.
While we do have a significant number of studies surrounding hip health and Hip Dysplasia prevention and treatment, it is important to reiterate that we do not have any concrete evidence to draw specific correlations between hip development and the use of baby carriers. The existing data, however, may serve as a launching point from which to conduct babywearing specific studies. It is necessary to draw realistic and logical conclusions from the information that is available, while avoiding the tendency to stretch the data beyond the scope for which it was intended. While there may be some disagreement within our industry regarding what types of conclusions are evidence-based, we can likely agree on the fact that it would be incredibly beneficial for our industry to fill the research gap with babywearing specific studies.
What we know:
- Hip health is important
- Not all babies are born with healthy hips
- Proper hip screening is important
What we DO NOT know:
- How does carrier type and positioning impact and/or promote long term hip health?
- What is “suboptimal positioning” and what is its impact on healthy hips and on hips that need correcting?
- How can babywearing be used effectively as an intervention for borderline Hip Dysplasia and what are the best practices for application?
Attachment, Bonding, and Kangaroo Care
Attachment and bonding are perhaps one of the most well developed areas of research that can correlate to the practice of babywearing, and it happens that this category contains some of the few babywearing specific studies available. While there are varied definitions of attachment, Bowlby and Ainsworth state:
An affectional tie that one person or animal forms between himself and another specific one— a tie that binds them together in space and endures over time (Ainsworth 1967) “The dimension of the infant- caregiver relationship involving protection and security regulation. Within this theoretic framework, attachment is conceptualized as an intense and enduring affectional bond that the infant develops with the mother figure, a bond that is biologically rooted in the function of protection from danger” (Bowlby 1982).
Attachment Theory research provides a theoretical framework that serves as a solid basis for the efficacy of babywearing with promoting attachment. Dr. Henrik Norholt of Ergobaby illustrates this correlation within his blog article Does Infant Carrying Promote Attachment, in which he analyzes attachment specific studies that highlight the potential for the practice of babywearing to promote bonding.
The benefits of babywearing in relation to facilitating attachment and bonding are also highlighted in Hold Me Close: Encouraging Essential Mother/Baby Physical Contact. Within this piece, Dr. Maria Blois provides analysis on the benefits of in arms carrying on secure attachment, and also highlights a study conducted in 1990 that sought to prove the efficacy of using soft baby carriers to promote infant holding. Blois provided the following summary of this study:
With the understanding that having access to a soft baby carrier can facilitate holding, one RCT specifically provided soft carriers to new moms to study the effect. In this trial (Anisfeld, 1990,) 49 mothers of newborn infants were randomly assigned to either receive a soft baby carrier or a plastic infant seat. Subjects were asked to use their product daily. Using a transitional probability analysis of a play session at 3.5 months, mothers in the soft baby carrier group were more contingently responsive to their infants vocalizations. When the infants were 13 months old, the Ainsworth Strange Situation was administered and more experimental than control infants were securely attached to their mothers. Authors concluded that mothers who were given soft carriers at birth were more responsive to their babies and the babies were more securely attached. (p.3)
While there is data to support the assertion that babywearing can promote attachment and bonding, the replication of such results through further studies would strengthen these findings and promote widespread normalization of the practice. Studies focusing on the use of baby carriers to strengthen attachment with non-maternal caregivers would serve to highlight the efficacy of strengthening familial bonds or the promotion of bonding within foster/adoptive caregivers as well.
Within the same vein as attachment and bonding, the known benefits of Kangaroo Care are correlated to the practice of babywearing. Kangaroo care is the practice of applying skin to skin contact with infants which, according to the March of Dimes, can reap such benefits as effective infant temperature regulation, more successful breastfeeding, promotion of bonding, and maternal confidence. Blois seeks to correlate the usefulness of baby carriers by stating “Given the many benefits of physical contact between mother and baby, it appears reasonable to encourage the essential practice of holding-promoting skin to skin contact, in arms holding, and holding in a soft baby carrier, as a matter of course in the care of new babies (both premature and term) and their parents.” (p.6) The babywearing industry seems to embrace the notion that baby carriers can help support kangaroo care, as demonstrated through the development of kangaroo care shirts, that mimic baby carrier positioning and form. Some anecdotal evidence showing the usefulness of babywearing and preemie specific kangaroo care within the babywearing community have been cited as well, such as these experiences documented by a parent of two premature babies. Such anecdotal evidence is useful as a resource for babywearing educators and those who wish to wear their premature babies safely. While the documented experiences of those who have used babywearing as a method of achieving kangaroo care can serve as an excellent launching point, it is important to note that there are not any existing studies to illustrate the efficacy of using baby carriers to facilitate kangaroo care, especially with premature infants. These kinds of specific studies are much needed within the babywearing industry so that we can determine the efficacy and safety of using baby carriers to facilitate kangaroo care, especially with premature infants; if studies deem the practice effective, we have further grounds from which to advocate for the use of these practices as a standard intervention with preemie and newborn care.
What we know:
- Babywearing has the potential to facilitate bonding and attachment
- Kangaroo care has statistically measurable, replicated success as an infant care practice
What we DO NOT know:
- How can babywearing function as an intervention for caregiver dynamics that experience barriers to attachment and bonding?
- How can babywearing support and facilitate kangaroo care?
- What are the impacts and outcomes of using babywearing as an intervention within kangaroo care, especially with preterm babies?
Safety and Positioning
Perhaps the most debated topic within the babywearing industry focuses on the topic of safety, and whether certain practices pose an inherent safety risk. As a babywearing educator frequently addressing questions regarding baby carrier safety, I often notice some confusion regarding “optimal” versus “safe” practices. Certain positions or carriers could be considered suboptimal, or less than ideal, but are not unsafe. The term “unsafe” is often used carelessly, especially when attempting to dissuade a certain practice or carrying method. The topic of babywearing safety is addressed thoroughly by such organizations as the BCIA and BWI, as well as babywearing schools and manufacturers, and generally centers around ensuring an open airway. Basic safety practices with baby carrier use have been shaped by past mistakes in carrier design or use, which are summarized within the CPSC Safety Standard for Soft Infant and Toddler Carriers Proposed Rule. Our industry has been profoundly influenced by the data contained in this report, as it provides us with the most serious risk factors – primarily fall hazards and infant deaths.
This unfortunate data–incidents of injury or death in a baby carrier–has become the basis of current industry safety standards and lays the foundation for our industry’s desire to promote practices that could prevent infant injury and death. Optimal practices are those that we deem from anecdotal evidence or studies from related disciplines–such as those discussed earlier in this blog article–to be ideal, but would not necessarily impact safety based on a lack of evidence of a safety threat. This is an area in which a great deal of research is lacking, yet many assertions are made without any conclusive data that a suboptimal position causes harm. Positions such as “cradle carry” often receives criticism based on the potential of airway constriction, yet there is often a disconnect between the position assumed in a bag sling–the type of carrier responsible for the vast majority of infant deaths in government-collected statistics– and a semi-reclined or upright cradle position where an open airway is able to be achieved and sustained. There can be some overlap if a carrier is used improperly, but cradle carry itself doesn’t cause injury or death; allowing baby’s chin to rest on their chest, however, may impair the airway and lead to positional asphyxiation. Areas like this are in great need of further research to shape evidence based practices and recommendations.
In addition to safe versus optimal positioning debates, there is often the assertion that babywearing positioning has the potential to prevent certain conditions or help achieve the same goals as tummy time. Like other areas discussed in this article, there might be some related research to show potential for these claims, yet no babywearing specific studies that correlate positioning with the claimed result. In the blog article Talking Heads: An Occupational Therapist’s Perspective on Positional Plagiocephaly and Babywearing, Sara Kift makes a very strong case for the potential of babywearing as an intervention for Plagiocephaly prevention. A thorough literature analysis highlighted a great deal of related scientific data to show the potential for efficacy, however as highlighted by the article, there are still not babywearing specific studies to support a conclusive claim.
Within our industry, we know that safe babywearing practices can make the difference between life and death, and maintaining an open airway at all times is paramount. We know that babywearing has the potential to support treatment and prevention of certain infant conditions, and to promote infant development. Data correlating the practice to such outcomes does not yet exist. We know that safe babywearing practices and positions are absolutely necessary at all times, yet without babywearing-specific studies, a conclusive correlation cannot be made between the practice of babywearing and the treatment of specific conditions..
What we know:
- It is important to ensure airway integrity with babywearing positioning
- It is important to inspect the baby carrier for damage prior to use
- It is important to keep baby’s face in view at all times
What we DO NOT know:
- To what extent (if at all) is “tummy to tummy” positioning superior in maintaining an open airway? Is cradle position inherently unsafe?
- What are the related benefits of babywearing specific upright positioning and impact on aspects such as core development, reflux management, etc?
- How can babywearing positioning support occupational and physical therapy endeavors for special needs situations?
- What are the impacts of using babywearing as a method of prevention or treatment for such conditions as plagiocephaly and torticollis?
While this has not been a comprehensive literature review, my goal was to highlight the fact that we have potentially more gaps within the research as related to our industry than we have known pieces. We will all have differing comfort levels when it comes to trusting and valuing research findings. What might feel more relevant to some, will feel less so to others. Despite the range of possible interpretations of the data we currently have available to us, one theme is prevalent: there is a clear lack of babywearing specific evidence. While that may not feel as significant to some, it feels highly relevant to me as a researcher, with the knowledge that what we assume to be true about babywearing and measurable outcomes may not actually result in proven outcomes. Until we have the opportunity to prove what we think to be true as babywearing educators, it is detrimental to make concrete assertions about best practices, and our responses to hot topics should reflect the level and quality of evidence we have available at this time.
What should we say when someone asks if narrow based carriers will harm their baby? That response will depend on the level of anecdotal evidence you have available, your personal beliefs about the relevance and weight of the research we have available, and your experience level with analyzing research. Despite our spectrum of experiences that will influence our beliefs on this topic, there is one known truth: we do not currently have enough babywearing specific research to make concrete assertions in many regards. We do not have incident report data to back up the notion that narrow based carriers will be harmful to a statistically significant degree. We do have data to show the importance of hip health and necessity of early screening.
My concern with these types of questions and the responses that are often thrown about, is that they reflect a lack of information availability and industry specific research. It is of vast importance that the general public has access to high quality information, rather than the information watered down by a game of telephone. In part 3 of this series, I will highlight efforts within our industry to increase the amount of relevant research available to the general public and measures being taken to fill those research gaps that plague our industry.
Blois, Maria. (2007-8). “Birth: Care of Infant and Mother: Time Sensitive Issues.” Gordon, W., Thafton, J. (Ed.), Best Practices in the Behavioral Management of Health from Preconception to Adolescence. (p. 108-132.) Los Altos, CA: Institute for Disease Management.
Bracken, J., Tran, T., Ditchfield, M. (2012). Developmental Dysplasia of the Hip: Controversies and Current Concepts. Journal of Pediatrics and Child Health. 48(2012). 963-973.
Garhart-Mooney, C. (2010). Theories of Attachment: An Introduction to Bowlby, Ainsworth, Gerber, Brazelton, Kennell, & Klaus. St. Paul, MN: Redleaf Press.
Click here for Part 1: Babywearing Research Common Misunderstandings
Click here for Part 3: Babywearing Research The Future of Babywearing Research