Skin to skin sleeping baby
In January, a study published in Pediatrics, the American Academy of Pediatrics’ flagship peer-reviewed journal, presented evidence in support of Kangaroo Mother Care (KMC) and its primary intervention: prolonged skin-to-skin contact (SSC) between a mother and her newborn child. I was originally asked to discuss this report at the time by the editors of The Scientific Parent, which is a great resource by the way, but I wanted to expand on my initial thoughts after letting them simmer for a bit over the past few weeks. Please check out the great work done by Leslie and Julia over at TSP after you finish this post.

Another media fail

As is often the case, the mainstream media picked up the story, as presented in a press release from Harvard’s School of Public Health, and blindly ran with it. Without exception the reports tout the benefits found in a specific subset of newborns, exaggerate and extrapolate those benefits inappropriately to all newborns, and make no mention whatsoever of potential risk (see these reports by Livescience, Reuters, and The New York Times). The Daily Mail decided to educate readers on “How ‘kangaroo’ care could SAVE your baby” and even the AAP’s own posted a glowing report on the study’s findings.

None of this is at all surprising given the study authors’ conclusions (and the media’s track record in handling complex medical topics):

KMC is protective against a wide variety of adverse neonatal outcomes and has not shown evidence of harm. This safe, low-cost intervention has the potential to prevent many complications associated with preterm birth and may also provide benefits to full-term newborns. The consistency of these findings across study settings and infant populations provides support for widespread implementation of KMC as standard of care for newborns. Additional research is needed to determine the ideal duration and components of KMC. Successful strategies for KMC implementation in various contexts should be disseminated among clinicians and policymakers.

As I will explain in today’s post, while there are absolutely some benefits in specific newborn populations, in most infants they do not appear to be clinically meaningful and there are undeniable risks associated with SSC. This risk includes severe injury to an infant’s brain and, as has been demonstrated around the world in numerous reports, even the possibility of death. That this risk has been ignored while endorsing an intervention for groups of newborns unlikely to reap objective benefit is upsetting to say the least. That this risk has not been addressed appropriately by medical professionals, organizations claiming to support the health of newborn infants, and government agencies tasked with protecting us from unnecessary harm is even more concerning.

What is Kangaroo Mother Care?

Kangaroo care, or more commonly just called skin-to-skin, is nothing new in the United States, although its implementation is quite variable from institution to institution. As a pediatric resident training at Vanderbilt Children’s Hospital over a decade ago, I remember encouraging monitored skin-to-skin contact in medically stable premature infants in the neonatal intensive care unit. We referred to it as kangaroo care as I recall. We also supported the practice in the NICU at Texas Children’s Hospital, also in medically stable kids being watched carefully. The current trend is to promote SSC in all newborns, even healthy term infants who will be staying in the room with their parent(s) and largely unmonitored. True KMC as practiced globally can be a bit different, yet it still varies depending on the available resources and the unique culture within and surrounding each individual facility.

As defined by the WHO, KMC involves “early, continuous, and prolonged skin-to-skin contact between the newborn and mother, exclusive breastfeeding, early discharge from the health facility, and close follow-up at home.” Infants are generally expected to be medically stable, so in the case of extremely premature or ill newborns this may mean that time lying against a caregiver’s bare chest is delayed for days to weeks. Some proponents consider this a problem because they feel that the stress caused by separation from the mother plays a significant role in why the baby is unstable in the first place, and they place great emphasis on SSC being initiated immediately after birth and uninterrupted. If “technology” must be added, they argue, it should be “with the baby in her SAFE place, on mother’s chest.”

The two mechanisms believed to be the driving force behind any potential benefits of KMC are SSC and breastfeeding, which proponents believe is more likely to be successfully initiated and maintained as the exclusive source of nutrition when KMC is prioritized. My goal with this post is to focus on the SSC component, which is the aspect of kangaroo care that contrary to the conclusions of the study in question, and pretty much all information available for parents online, does pose a significant risk to newborns as commonly practiced.

What did the new study actually show?

The study in question is a systematic review and meta-analysis of available published and unpublished data from 2000 to 2014 that involved some amount of SSC, even if the full WHO KMC criteria were not met. They excluded small studies of less than ten babies as well as studies that looked at subjective outcomes or that didn’t include a control group. Any quantitative endpoint was accepted, and when all was said and done 124 studies from countries around the world were found to be acceptable.

Among the outcomes included in the analysis were mortality, breastfeeding initiation and exclusivity, infection, heart rate, respiration, oxygenation, temperature, blood glucose and cortisol levels, length of initial hospitalization and readmission rate, growth, and pain response. The individual studies in the meta-analysis also contained numerous additional outcome measures that the authors were unable to finagle into a summary measure because of their one-off nature or the excessive heterogeneity in trial methodology. So what did they find?

The study’s big finding, and the one which the media jumped on, was that when a baby lives long enough after birth to undergo some amount of SSC there was a statistically significant decrease in mortality out to 3, 6, and 12 months compared to babies that did not. But this effect was only found to be truly significant in the subgroup of low birth weight (LBW) babies that were born weighing less than two kilograms. It did not appear to matter in which country the child was born or what the available resources were. It also did not seem to matter when SSC was initiated or how much the child received, which is curious.

In addition to the benefit of increased survival in that specific population, the study revealed a relationship between SSC and a moderate, across-the-board increase in exclusive breastfeeding up to 4 months of age, but did not show an effect of SSC on how quickly breastfeeding was initiated, which is one of the major benefits touted by proponents. SSC also appeared to lower the overall risk of newborn sepsis, but not any other type of infection, to improve regulation of blood sugar in LBW newborns only, and to lower the chance of hospital readmission slightly. Findings of differences between groups receiving SSC in vital signs, growth, and every other outcome were negligible and unlikely to be clinically relevant in most babies, such as a reduction in respiratory rate by three fewer breaths per minute. They were unable to demonstrate a dose response curve for any outcome, which also raises some interesting questions.

And now that risk nobody is talking about

I agree that a low-tech intervention like SSC is potentially beneficial in many babies, particularly in regards to premature and low birth weight infants, and it is certainly inexpensive. While the effects may not be substantial in healthy babies born at term and at an appropriate weight for their gestational age, reducing metabolic distress and stabilizing blood glucose levels in more medically fragile newborns is probably a good thing. And it appears that the most meaningful potential benefit, reduced mortality in low birth weight newborns, is realized even in resource rich regions like the United States.

Based on prior research, particularly in premature infants and in breastfeeding outcomes, there has already been a significant trend for this kind of intervention to be promoted by pediatric-focused organizations like the AAP, by private organizations like “Baby-Friendly USA “, as well as the CDC (which emphatically recommends that all hospitals be “Baby-Friendly”), and the WHO. Their intention for the most part is to have policies in place that support early and successful breastfeeding. These organizations also stress the importance of so-called “rooming in,” and increasing numbers of hospital in the U.S. are doing away with the option for a child to leave the mother’s room for any reason, even maternal pain or exhaustion.

When a mother spends time holding her newborn baby against her skin soon after delivery, there is good reason to believe that this may help improve breastfeeding success when exclusivity is the desired result. And it is a great way to help cement the connection between a mother (dad too) and her child. But it must be pointed out that both of these outcomes can and generally do occur even if no SSC takes place at all. I really have to stress that you are still a good mother even if you aren’t attached to your baby 24 hours a day, as recommended by some KMC proponents.

So KMC and SSC are promoted as a panacea for many newborn issues despite the lack of solid evidence for most objective outcomes in the average baby. When something is too good to be true, of course, it usually is. This is especially true in medicine where there have historically been a grand total of zero truly risk-free interventions. The media reports and the study conclusions that they are based on are flawed in at least one very important way, and this is likely putting babies at risk of injury to their brain and even death. There is in fact very good reason to suspect that SSC as commonly recommended, and in the current “baby-friendly” climate experienced in many hospitals, is a risk factor for something known as sudden unexpected postnatal collapse (SUPC).

What is sudden unexpected postnatal collapse?

SUPC occurs when a low-risk newborn without signs or symptoms of illness or injury has a sudden and unexpected episode of cardiorespiratory insufficiency within the first week of life, often occurring in the mother’s hospital room within the first few postnatal hours. The terminology used in reports around the world varies, with early SIDS, severe apparent life threatening event (ALTE), and sudden unexpected early neonatal death (SUEND) being common. But what doesn’t vary is that the outcome is frequently tragic. Roughly half of the children in these events die and many of the remaining newborns become disabled because of a period of low oxygen supply to the brain.

How common is SUPC? Thankfully, the overall incidence in low-risk (healthy term and near-term) babies is very low, but exact incidence figures are challenging because of different definitions and inclusion criteria used is the literature. This extensive 2013 review of the literature, which found highly variable rates ranging from 3/100,000 to more than 100/100,000, concluded that many studies have likely underestimated the true risk. To put this in perspective, the CDC and AAP have recommended the universal intramuscular injection of vitamin K into newborns within the first hour of life since the 1960s in order to prevent serious bleeding events that occur with a frequency of less than 10/100,000.

Although impossible to peg down exact numbers, the authors estimate that even with the lowest reported figures there could be 500 SUPC cases and around 150 newborn deaths out of 5 million births each year in the European Union alone. In reality, it is likely to be much worse than that. In comparison, there are roughly 4 million babies born in the United States annually which means that if investigated, SUPC would likely represent one of the most common causes of death in healthy term newborns.

Their literature review found 400 cases of SUPC documented within the first week of life. These were cases where they had enough information to rule out complications (premature birth, illness, injury, etc.) that increased the likelihood of collapse. They discuss 3 published cases that exemplify the range of SUPC presentations in detail, all of which occurred during SSC with a baby in the prone position (face down), something that pediatricians have universally recommended against since 1994.

During their review of the 400 well-documented SUPC cases, the authors found that three out of every four were associated with prone positioning of the infant, typically during SSC and initial attempts at breastfeeding. Their findings fall in line with other reports that have listed “prone positioning, first breastfeeding attempts, cobedding, mother in episiotomy position, a primiparous mother, and parents left alone with baby during first hours after birth” as risk factors. I hope this makes it clear how absurd and potentially dangerous the claim that SSC “has not shown evidence of harm” is.

SSC is a set up for the biggest risk factor for SUPC and potential death of an otherwise healthy newborn baby: prone positioning during sleep. And it isn’t just infant sleep I am worried about. Prolonged SSC in the early days of a baby’s life is very likely to result in infant prone positioning, often with their face pressed against the mother’s chest and breast, while the exhausted mother is also asleep. This is known as bed sharing, and it is a well-documented risk factor all on its own.

The scenario that increasingly is becoming the norm in many countries, and which is most likely to result in SUPC, not to mention an increased risk of a baby falling out of the bed and suffering a head injury, is a tired mom lying in bed in a quiet, dimly lit room that promotes “rest”, a lack of nursing presence in the room or monitoring of the baby for long stretches of time, and SSC. In many cases this scenario is encouraged without discussion of the potential risk. It should now be clear how CDC and WHO endorsed programs like “Baby-Friendly” might increase the likelihood of an overtired mother falling asleep during SSC.

What causes SUPC?

Why are newborn infants at increased risk of SUPC during SSC? If you think about it, it makes perfect sense. First and foremost, and especially during the first few hours of life when most of these incidences occur, this is a time of transitioning. The first 24 hours of life is typically a very sleepy period where newborns have diminished responsiveness to the outside world. They often barely arouse even with feeding attempts.

As in SIDS, there is likely some vulnerability in the brain during this pivotal period of development. When a baby is stressed by an environmental insult, such as being deeply asleep and lying prone against the body of an exhausted mother, this might result in failure to arouse, cessation of breathing, decreased oxygenation, and ultimately SUPC. And some babies are simply suffocated by their sleeping mother. Even more terrifying is the fact that this can occur while dad and other family members are admiring the beautiful, but dead, new arrival and the peacefully sleeping mother, the unfortunate outcome discovered only when a nurse comes by to grab a set of vitals.


Don’t get me wrong. I don’t mean to throw the baby out with the bathwater. Although perhaps exaggerated, there are some potential benefits to SSC. It isn’t anything earth shattering in healthy term infants of appropriate size, but I’m not going to tell a mother that her subjective experience while holding her newborn child against her bare skin is wrong or a waste of time. And even in appropriate weight term infants SSC may help establish breastfeeding or reduce the likelihood of sepsis. My desire is for hospitals and healthcare providers that take care of mothers and babies to be honest about the risks and provide a safe environment for the intervention, and I’m hardly alone in this observation.

In order to reduce the risk of SUPC during SSC, hospital staff and pediatricians must first recognize which newborns may be at particular risk and provide appropriate monitoring. A term and well-grown newborn whose mother was on a medication that may result in a sedated baby would be just one of many examples. If a nurse isn’t available to monitor the child continuously (family members don’t count), then perhaps unobtrusive monitoring of the child with continuous pulse oximetry, as is standard in Japan for SSC in all newborns, would be appropriate. In fact, I wouldn’t have a problem with following their lead on this.

Education for the family is just as important. They should be given appropriate information regarding SSC that includes the risk of SUPC in order to decrease the likelihood of a collapse taking place after leaving the hospital. Supine positioning and maintenance of an open airway should be encouraged, as should all SIDS risk reduction strategies for that matter, and the mother should be advised to place the baby in the bassinet or hand them off to another caregiver if she is feeling sleepy.

Posted by Clay Jones

Clay Jones, M.D. is a pediatrician practicing at Newton-Wellesley Hospital in Newton, MA, and a regular contributor to the Science-Based Medicine blog. He primarily cares for healthy newborns and hospitalized children, and devotes his full time to educating pediatric residents and medical students. Dr. Jones first became aware of and interested in the incursion of pseudoscience into his chosen profession while completing his pediatric residency at Vanderbilt Children’s Hospital a decade ago. He has since focused his efforts on teaching the application of critical thinking and scientific skepticism to the practice of pediatric medicine. Dr. Jones has no conflicts of interest to disclose and no ties to the pharmaceutical industry. He can be found on Twitter as @skepticpedi and is the co-host of The Prism Podcast with fellow SBM contributor Grant Ritchey.