At face value it seems to make sense, if babies are crying because they want to be (need to be) held but can’t be held because their caregiver needs to get other things done, then viola! Just use an infant carrier and crying is reduced.

But it’s not quite that simple– the crying or the research.

Attachment

Attachment Parenting proponents would argue that babies are crying because they don’t have a secure attachment to their caregiver and to develop secure attachment babies need to be, well, attached. The AP community (like many others) has had a long and conflicted relationship with science, rejecting what doesn’t fit and oversharing-to-death any studies with titles that appear to support their ideology without actually reading them. (Yes, I’m picking on the APer’s. I used to be one and I know they can do better once they know better.)

The now infamous Hunziker-Barr study from 1986 titled, “Increased Carrying Reduces Infant Crying: A Randomized Controlled Trial” is one of these studies being endlessly, endlessly cited.

The big problem with sharing research after only reading the title or at most the abstract is that you don’t know the details. (But golf clap for having a citation!) For example: what did the study really look at? What methods were used? What did the peer-reviewers have to say about it?

And because the scientific method relies on replication, it’s very important that subsequent research be taken into account. Have other studies looked at this issue? What has subsequent research shown about carrying and crying?

But before we even get into all that: why is crying such a big deal?

And: If babywearing doesn’t actually reduce crying, is it worth it?

“Babies just cry, so what’s the big deal?”

In the west, especially in North America, infant crying has been a focus of research since the baby boom of the mid-20th century. In the following decades, scientists determined which direction, speed, and amplitude of rocking best-soothed infants in bassinets. They did not, however, recognize that the up and down movements with a wide sway, at approximately 90 beats per minute, more or less reproduced the sensation of being held by an adult who is walking. Through observational studies, scientists determined that infant crying peaks at around five weeks of age, that male infants cried more than female infants and that newborns don’t produce tears until one or two months of age. /whew!/

Dolls From Hell

The underlying assumption of this research was that babies cry for no good reason, it’s just their biology. The concept of the irrationally crying infant is so pervasive that in recent decades highschoolers in the United States are sent home with computerized dolls (one brand is Baby Think It Over) that will play audio of a crying baby at random, sometimes for hours, with zero accompanying body language, as a means to scare teens out of sex– er, well, the companies leasing these dolls to public schools claim to teach teens about responsibilities of sex and parenthood but the product fails miserably because those dolls do not teach comprehensive sex ed or anything about caring for actual infants. And parenthood is not a punishment for having sex, ffs.

Real babies don’t just make crying sounds, there are always preceding and accompanying body language to their crying. Yes, some babies cannot be soothed for hours, but with real infants, there is always a person behind the crying. Unfortunately, the traumatic experience of dealing with these Dolls From Hell can color a person’s attitude to actual humans who are crying but just happen to be infants at the time.

Science of Crying

We are starting to develop a more nuanced understanding of infant crying, for example, it is understood that in addition to crying as a response to fear and pain, infants may cry for thermoregulation before they are able to shiver at around two months of age (Barr, 2001). Ultrasounds have shown fetuses crying in the womb leading to questions about whether ultrasounds, especially 4-D, produce pain in the fetus. Science has made it possible to look inside the womb in real time but has yet to find a cure for infant crying. But does it require a cure?

Crying can adversely affect the health of infants and their caregivers. For example, because colic, which is inconsolable crying starting around six weeks of age for 3+ hours a day, 3+ days a week, for 3+ weeks. It is culturally associated with digestive complaints and parents may give up on breastfeeding or prematurely introduce solids. This puts infants at increased risk of illnesses, childhood obesity, and potentially aspiration of baby food, even though there is no evidence that colic is caused by digestive issues.

Parents may turn to dangerous pharmacological interventions, such as repeatedly dosing an infant with Benedryl, pain reducers, or other drugs risking serious side effects and even death. In the UK, the drug dicyclomine hydrochloride was prescribed for infants with excessive crying but due to fatalities, the manufacturer warned against its use in infants (St. James-Roberts, 1995).

Sleep deprived parents have forgotten their baby in hot cars leading to injury and death. Parents report feelings of anxiety and low esteem related to infant crying. In some cases, infant crying has affected the parent’s ability to form a healthy attachment and at worst, create an abusive situation (Cock, 2015). For example, some parents use “cry-it-out” methods of controlled neglect and infants under two-months (the supposed crying peak) are the most common victims of abusive head trauma among children under two years of age.

The prospect of there being a magic cure-all for infant crying and the reduction in the associated risk for infant abuse and death seems almost too good to be true. This is why the conclusions of the 1986 Hunziker study are so tempting: if supplemental carrying really is all it takes to reduce infant crying, scientists and doctors could finally offer a solution to desperate parents.

The Hunziker-Barr Study

In 1986, a study was published concluding that three hours of “supplemental” carrying reduced crying in newborns. The results sound impressive: infants in the supplemental carrying group cried 43% less overall and 51% less during the evening hours than infants who were not given supplemental carrying. Contemporary babywearers often share these statistics to encourage people to try using infant carriers. However, the participants in the study weren’t using the infant carriers provided.

For this study they describe “normal” infant crying in “industrialized societies” as increasing from birth to 6 weeks of age, declining until around 4 months though maintaining crying in the evening hours.

Over the course of five months in 1983, 234 mothers were approached in the maternity wards of two hospitals in Montreal. The infants had to be breastfed, first-born, with normal birth weight after an uncomplicated pregnancy and birth. The mothers were told what would be expected of them during the study, i.e. they may be randomly selected to carry their infant for an extra three hours during the day in addition to the carrying needed for feeding and responding to crying, and that they would be given a soft carrier (front, inward facing).

Only 50% (117) of those asked agreed to participate beginning with 3-week old infants and by the end of the study, another 18 had dropped out for a variety of reasons which are common to newborn studies (e.g. the moms were too busy to complete the diaries, etc.), and the researchers noted that those who left the study tended to be poorer.

Infants were randomly divided into either the supplemental carrying group or the control group. However, in terms of sex, there were many more boys in the supplemental group than girls (30/19) and in the control group, there were more girls than boys (29/21). There were 5 non-white infants in the supplemental group and 6 in the control group (each group had 44 white infants).

Parents were provided diaries to fill out detailing when and how long their babies cried, as well as what the researchers believed was unrelated to carrying, such as hiccups and vomiting. Crying was considered by both duration (hours per day) and frequency (episodes per day), for example, my baby cried four times today, once for five minutes and another time for two hours.

During the first week of the study, the infants in both groups cried similar amounts in a similar pattern throughout the day. Then the supplemental carrying group began to change in both frequency and duration, while the control infants showed an expected peak at six weeks of age, there was no peak for the supplemental carrying group.

The “peak” of crying in the supplement group was the start of the study at 3 weeks. At 6 weeks the supplemental group cried 43% less than the control group, at 8 weeks 41% less and at 12 weeks 23% less throughout the day. If only the evening hours are taken into consideration, there was a 54% reduction in crying at 6 weeks and 47% reduction at 8 weeks. Carrying increased in the supplemental group to around 4.4 hours per day but most interestingly, less than one hour on average in the carrier, the rest of the carrying was in-arms, while the control group carried on average 2.7 hours per day.

Hunziker and Barr note that the increased carrying includes many interventions for soothing infants, including the proprioceptive stimulation of carrying, the proximity to their mother’s sounds and smells, and the speed at which non-crying cues could be recognized and responded to, it wasn’t just carrying. And they note that anticipatory carrying, i.e. carrying before any crying occurs, may make the carrying more effective at preventing excessive crying disorders, like colic, which makes an infant unresponsive to carrying.

The takeaway: increased carrying in-arms reduced crying in healthy, firstborn, breastfed babies in middle-class, predominately white, families in Montreal who self-selected to be part of a study on increased carrying.

How about subsequent studies?

1995 St James-Roberts, et al.

In this study, the researchers explained that infant crying is linked to parental stress and infant abuse, as well as a burden on the UK’s health care system. They describe the three most common forms of intervention on “excessive” infant crying from a medical perspective and why they refuted them:

1. Pharmacological (i.e. drugs)
   • Only one drug was reliably effective but it caused reactions and possibly fatalities
2. Dietary changes, either changing nursing parent’s diet or the baby’s diet, most commonly, eliminating dairy
   • Of non-breastfed infants, only a very small percentage of infants are sensitive to cow milk
3. Changing parental care styles, for example, increased carrying, etc
   • They believe that self-selection bias played into the results of the Hunziker-Barr study as 50% of the invited participants refused to take part.

The study also considered other research, often contradictory, regarding parental styles changes for infants already presenting with “excessive crying”: Taubam prescribed more stimulation, McKenzie prescribed less; interestingly both of these interventions dealt with how much an infant is carried.

So to test the third intervention, changes to parenting styles, newborns from a UK hospital’s maternity ward were recruited to a study to test the effectiveness of supplemental carrying versus increased parental responsiveness on rates infant crying at 2, 6, and 12 weeks of age. There were three groups:

1. Increased carrying in a “proprietary baby sling made of soft material”
2. Increased responsiveness which included instructions to never let their baby cry
3. Control group.

Infant crying was recorded in parental diaries, audio recorded via a microphone in a stuffed toy that needed to be kept with the baby at all times and within 100m (328ft) of the receiver, and questionnaires.

The conclusion: there was no difference in infant crying regardless of intervention.

“Because advice to increase carrying is also no more effective than parental education as a treatment for infants with established colic, it seems likely that widely applicable approaches to successful prevention and treatment of infant crying problems are neither simple nor close at hand.”

St James-Roberts, 1995

What I found interesting was that the researchers considered increased carrying and increased responsiveness as different groups, though they noted that the increased responsiveness group carried and fed their babies more often,

“Mothers in the responsiveness-intervention group also increased the amount they carried their babies while settled, to a level in between the amounts in the carrying-intervention and control groups”

ibid.

2002 Elliot, et al.

This study defines “normal” infant crying as two hours per day, peaking during the second month and tapering off until the fourth month of life. They noted that infant crying can cause problems for parents and infants bonding as well as responsiveness later in the life of the child. They suggest that solving the problem of infant crying would make for healthier and happier families. 

So they set about to study two interventions, separately and together. They divided participants into four groups:

1. supplemental carrying 
2. infant massage
3. supplemental carrying and massage
4. control group.

The study found that the combination of infant massage and supplemental carrying had the greatest reduction in infant crying (and even then it was very minor <p=0.6), which was followed by Group 1’s supplemental carrying and then Group 2’s infant massage.

“More than one soothing technique used together to be more effective in soothing crying infants than using a single technique”

Elliot, 2002

My Criticism

So we’ve reviewed these studies looking at the influence of carrying versus other interventions on infant crying. As an academic, I was trained to rip these studies a new one in order to help make subsequent research better. (But I’ll be gentle this time.)

First of all: What did the carriers look like? In Hunziker’s study, the participants used a carrier less than a quarter of the time they held their babies. In the St. James-Roberts study, “… mothers were given proprietary ‘baby slings’ made of soft material to assist with carrying their infants…”. There is no mention of whether the supplemental carrying group was taught how to use the carriers or whether the subjects were comfortable using the carrier.

(I mean, have you seen the baby slings of the 1980’s and 90’s? No thank you.)

Defining carrying is an issue in all the studies: is it holding the infant while stationary? While walking? I have met new parents who were so terrified of their newborn shattering in their hands that they would barely breathe while holding their baby, let alone walk around.

What position is the infant being carried in? My guess, considering that even participants with carriers chose not to use them, is that they could more comfortably hold their baby upright, in-arms, rather than reclined in an unsupportive sling typical of styles available in the 1980s and 1990s. See Shana above– not even the model feels safe letting go of the baby for the split second it takes to snap a product photo.

And though the audio recordings give more weight to the results in terms of how much crying occurred, it’s not exactly convenient for carrying around with a baby. And having to keep it within range of the receiver? Not conducive to a walk around the block.

“The need to keep the teddy-bear transmitter near the baby was stressed; the teddy bear included a carrying strap for use when the baby was carried”

St James-Roberts, 1995

I don’t know about the participants but this wouldn’t really encourage me to carry my baby while I was getting things done. Especially not in a 1990s closed-tail, stuffed-rail floral-minger death-trap ring sling with a teddy bear on a strap. Très chic. Just because someone has a baby doesn’t mean they lose their dignity.

Carrying is Experimental

The major thing to remember with these studies is that they were studying carrying as an experimental group. Carrying one’s baby was not considered a part of the participants’ culture, the control groups in all of the studies only held their baby for feeding and possibly briefly to respond to crying.

2008 Bonichini, Sarah, et al.

As a counterpoint to experimental carrying studies, in 2008 a study of Italian mothers sought to confirm the peak of infant crying at 5 weeks of age. However, the researchers failed to find a peak of crying, instead, they found a peak of mothers holding their babies, carrying them around as they went about their day, especially in the evenings when North American and other European parents report the most crying. The researchers encouraged noting cultural differences in infant carrying before determining biological norms for infant crying.

The Purpose of Crying

“Early infant crying is an adaptive behavior that acts to promote mother-infant proximity and to provide opportunities for social interaction […] The increased carrying reduces crying behavior but promotes proximity so that crying is less necessary.”

Hunziker, 1986

It is theorized that one of the reasons humans are born with secondary altriciality (physical helplessness with fully developed senses) is for social learning. Human infants are helpless at birth to ensure that many people are needed to care for them This helps babies learn about their world and their culture before they are able to/before they need to do anything for themselves. So what happens when those conditions aren’t being met? When instead of human faces, human language, and human touch they are met with toys, baby-holding devices, mirrors, electric screens and/or the ceiling… crying may be their last ditch effort to get human attention.

Conclusions

The published research is contradictory on the subject, experimental studies tend to find no basis for supplemental carrying reducing infant crying, yet observational studies of cultures with a tradition of “supplemental” carrying show significantly less infant crying. Perhaps there is some missing element.

The people who self-selected for the Hunziker study may have had a different approach to parenting as a whole, a kind of sub-culture of crunchy granola types (though they still gave birth in a hospital) developing a tradition of infant carrying (or proximal parenting) which may have included other “interventions” like cosleeping and the extensive use of allomothers. And as so many of the studies suggest, having multiple interventions is more successful at reducing infant crying. It may well be that those already intending to practice “supplemental” carrying, by choice or tradition, employed multiple cry-reducing practices in combination with carrying.

“The actual physical presence or proximity of the infant may have effects on the mother, making her more aware of and thus more responsive to her infant’s needs and states. A mother can more easily recognize prodromal signs of hunger or discomfort in a carried infant than in an infant in a crib or stroller at some distance from her.”

Anisfeld et al, 1990

Based on available research, the Hunziker study is an outlier. And it should be stressed that even in the Hunziker study, the parents weren’t really utilizing infant carriers (for whatever reason). They certainly weren’t “babywearing“.

Though I have only brought up two other studies from the last 30-odd years showing no reduction in crying with supplemental carrying, there are many more to choose from with similar results.

Perception of Crying

But even in cases where babywearing does not reduce crying in infants, it can still help with the caregiver’s perception of the crying.

In Elliot’s study, parents who carried their infants more tended to have more positive interactions with their infants and developed a higher perception of their infants and their ability to care for them.

This is very important as parental perception, rather than infant crying, is the determining factor in infant abuse. We shouldn’t be blaming the victim, as Sheridan and Wolfe pointed out in their Lancet article, If Only You Hadn’t, I Would Not Have Hit You: Infant Crying and Abuse,

“… infant behaviours are not the most salient variable in provoking abuse when they found that it was the parent’s perceptions of their child’s behaviour that were of greater significance than the actual behaviours of the infant.”

Babywearing may or may not reduce the frequency or duration of infant crying, especially in newborns, but that may be the wrong question to ask when it comes to why we carry our babies. Babywearing provides physical, emotional, and social benefits to both wearer and wearee beyond its ability to prevent or reduce crying by providing the kind of unconditional support for parents, caregivers, and infants need.

---

If you appreciate this kind of research please consider becoming a Patron of The Baby Historian.

---

Sources:

Anisfeld, Elizabeth, et. al. 1990. “Does Infant Carrying Promote Attachment? An Experimental Study of the Effects of Increased Physical Contact on the Development of Attachment.” Child Development, 61: 1617-1627.

Baildam, E M, V F Hillier, S Menon, R P Bannister, F N Bamford, W M O Moore, and B S Ward. 2000. “Attention to Infants in the First Year.” Child: Care, Health and Development26 (3): 199–216. https://doi.org/10.1046/j.1365-2214.2000.00144.x.

Barr, Ronald G., Ian St. James-Roberts, and Maureen Keefe, eds. 2001. New Evidence on Unexplained Early Infant Crying: Its Origins, Nature and Management. Skillman, NJ: Johnson & Johnson, 2001.

Bonichini, Sarah, et al. 2008. “Infant crying and maternal holding in the first 2 months of age: an Italian diary study.” Infant and Child Development 17 (6): 581-592. https://doi.org/10.1002/icd.565

Cock, Evi S.A. de, Jens Henrichs, Catharina H.A.M. Rijk, and Hedwig J.A. van Bakel. 2015. “Baby Please Stop Crying: An Experimental Approach to Infant Crying, Affect, and Expected Parenting Self-Efficacy.” Journal of Reproductive and Infant Psychology 33 (4): 414–25. https://doi.org/10.1080/02646838.2015.1024212.

Elliott, M. Ruth, Sandra M. Reilly, Jane Drummond, and Nicole Letourneau. 2002. “The Effect of Different Soothing Interventions on Infant Crying and on Parent-Infant Interaction.” Infant Mental Health Journal 23 (3): 310–28. https://doi.org/10.1002/imhj.10018.

Esposito, Gianluca, et. al. “Infant Calming Responses during Maternal Carrying in Humans and Mice.” Current Biology 23.9 (2013): 739-45. Web. 15 July 2015.

Hunziker, A. U., and R. G. Barr. “Increased Carrying Reduces Infant Crying: A Randomized Controlled Trial.” Pediatrics 77 (1986): 641-48.

Pederson, David R. “The Soothing Effects of Vestibular Stimulation as Determined by Frequency and Direction of Rocking.” Ontario Mental Health Foundation 84.1 (1973). University of Western Ontario, London. Dept of Psychology.

Sheridan, Clare, and Nancy Wolfe. 2004. “If Only You Hadn’t, I Would Not Have Hit You: Infant Crying and Abuse.” The Lancet 364 (9442): 1295–96. https://doi.org/10.1016/S0140-6736(04)17204-8.

St. James-Roberts, Ian, et. al. “Supplementary Carrying Compared With Advice to Increase Responsive Parenting as Interventions to Prevent Persistent Infant Crying.” Pediatrics 95.3 (1995): 381-388.