Strollers, Baby Carriers and Infant Stress
By Elizabeth Antunovic
Being carried or worn in an upright position with proper leg support is not only developmentally sound but often preferable to mothers and babies alike.
Europe seems to host the most pediatricians who recommend that, in order to avoid pressure on their underdeveloped bodies, newborns and infants lay flat on their backs in a stroller and not be carried. Yet, laying a young infant on his back alone in a stroller is actually physically and emotionally stressful and can be developmentally inhibiting. Being carried or worn in an upright position with proper leg support is not only developmentally sound but often preferable to mothers and babies alike. Upright carrying optimizes the physical, emotional and intellectual growth of your baby.
Infant Spine Development
Our spine is not perfectly straight, even though it may appear so from the front or back. When you look at a person from the side, four slight curves are visible, forming an elongated “S” shape. These curves help keep us flexible and balanced. They also help to absorb stresses placed on our bodies through daily activities that impact our spine like walking, running and jumping.
We weren’t born with these curves. Normal curves of the spine develop gradually as a means of adapting to gravity. At birth, babies are in a state of flexion, still curled up, with their spine in a natural long c-shaped (convex) curve. At first, a baby does not have the strength to hold his head up, nor the balancing curves in his spine to do so. But gradually as the muscles in his neck get stronger, he begins to lift his heavy head against gravity, and a curve starts to develop in his neck (the cervical curve) to help balance his head. When your baby starts to creep and crawl the lower back (lumbar curve) and the muscles that support it develop. Only by about the first year does your baby attain these curves in his spine (Leveau, 1877).
The Stresses of Laying Flat
Laying your infant flat on his back stretches the c-curved spine into a straight line, against his natural shape. Research shows that keeping an infant’s spine straight is not a sound physiological position. In addition to stressing the baby’s spine it can also negatively influence the development of your baby’s hip joints (Kirkilionis, 2002).
Laying Horizontal Causes Physical Deformities
Not only is spending most of the day flat on your back bad for your hips but infants who lie frequently on their backs in a stroller may end up with plagiocephaly (deformed skulls, flattened on the back or side) and deformed bodies with poor muscle tone (Bonnet,1998). Research backed by the American Academy of Pediatrics states that “with prolonged immobilization on a firm mattress or a flat bed (as in a stroller), the constant influence of gravity flattens the body surface against the mattress producing positional disorders and infants with decreased muscle tone (Short, 1996)”.
Existence in Containers
This does not mean that laying flat for a couple of walks around the block in a stroller is going to wreak havoc on your baby’s physical development. But the truth is that the average Western infant between three weeks and three months of age is carried a little more than two and a half hours a day (Heller, 118.) We end up carrying the baby to the car in a container, through the store in a container, to eat lunch in a container, back to the car in a container and home in a container*. Sometimes from there to the swing that we can click right into without touching the baby so we can make dinner, into the bouncy seat while we eat, and soon after to sleep in a crib. The west has diverged from eons of child rearing and has gotten to the point so that objects are defining our baby’s existence more so than our bodies.
“To remove the newborn baby from his mother and place it on its back or on its front on a flat surface, often uncovered is to fail to understand the newborn’s great need for enfoldment, to be supported rocked and covered from all sides, and that the infant may only gradually be introduced to the world of more open spaces. From the supporting, continuous, tangible presence of his mother the infant will gradually come to move some distance toward the outside world”. (Montagu, 294)
*Please note that the author does not mean to imply that a baby carrier should replace your car seat for transport while in the car. Never drive or carry your baby in the baby carrier while in a moving vehicle.
The Fetal Tuck
Newborns are almost impossible to stretch out unless wrapped or swaddled. When you place an infant flat on his back, his thighs will usually be pulled up towards his chest (Schon, 2007), or when sleeping straddled and bent in a frog position. “The fetal tuck, the natural position of babies is the most calming and the most adaptive.
Infants use less oxygen which conserves energy and waste less calories. They digest their food better. It is also the best position for thermoregulation because of reduced stomach exposure. Also, we have more efficient temperature regulating cells and more fat on the back side of our bodies as well. When we hold our infants stomach- to- stomach we are protecting all the receptor and vital organs (Montagu, 1986).
The instinctual flexed widespread legs that an infant maintains when picked up, coupled with the palmar plantar reflex that helps an infant to cling to his mother, suggests that infants little bodies are adapted to be carried upright and oriented toward their mothers.
The Trouble with Car Seats
If the stroller positions the baby in a somewhat upright position (such as in infant car seats) it may be gentler on the baby’s c-shaped spine in that it is not stretching it flat. But car seats are not a much better option for transporting your little one. Research by the International Chiropractic Pediatric Association shows that car seats are not the ideal transport for your infant when not in the car, due to “restricted postural options which can impact your baby’s developing cranium and spine” (International Chiropractic Pediatric Association).
By keeping the spine in a c-shaped configuration, these contraptions can actually prevent and inhibit the natural curves forming. Babies can have a hard time acquiring adequate muscle strength to hold their big heads up if they don’t get much of a chance to deal with gravity.
Positive Physical Development
When infants are held upright, however, they are allowed to practice compensatory movements, enhancing muscular strength and allowing for more control over their fine motor skills. When the mother walks, stops, or turns an infant’s body naturally works against the pull of gravity to maintain his position.
The force of gravity is a positive element in infant development allowing infants to learn from early on to hold their heads up and keep their bodies clinging to the mother and balanced in equilibrium.
Discord with Upright Carrying
So why do some still claim that the horizontal position is better for your infant? The physiological arguments as to why a baby should be transported in a horizontal position for his first months of life seem to stem from the assumption that the upright position may be stressful to his underdeveloped spine and pelvis.
Although some pediatricians are advocates of natural parenting, many don’t have that much hands on experience with baby carriers. They may be acquainted with the upright carriers from the eighties and nineties with the typical lack of adequate head/neck support, tight or chaffing leg holes, resembling a parachute harness and a complete lack of leg support. Perhaps they have seen so many babies facing out when carried upright that they assume all upright carrying is non-supportive.
The image above is perhaps the carrier that many doctors imagine and classify as unsafe or harmful. It is a non-physiological carrying devices. Front facing carriers unlike, wraps, slings, mei-tais and soft structured carriers, do not provide proper leg support which can make their pelvis’ tilt backward and place them in the dangerous “hollow back position”.
Not facing the carrying adult, and facing out their center of gravity is off. Pressure is placed on the baby’s shoulders and the chest area, often retracting the shoulders and hollowing the back even more. Facing out is a non-physiological position that places pressure on the inner thighs of the baby and the base of the spine. Upright carrying facing out is stressful on babies.
The wider base of the above carrier would provide some spinal support (maintaining the natural convex “c-shape”) if the baby was turned facing the father and his bottom was seated in it. Instead the baby’s spine is straightened and often hyper extended (concave “hollow back” shaped) due to weak abdominal muscles and lack of leg support.
Although the baby does benefit from being carried close to his mother, facing out in this position there is no leg support, improper spine and hip support, and no head or neck support if the baby falls asleep.
Swaddling Infant Legs linked to Hip Dysplasia
Although there are myriad psychological, emotional and physiological benefits from the swaddling style of the Navajos, there is clear evidence that swaddling the legs so that they were bound together and not allowed to flex at the knee or at the hip, has lead to hip abnormalities (Crisholm, 1983). In the case of the Navajos, stress to the hips of the infant was not caused by the upright positioning but from improper leg support, by not allowing the legs to spread or the knee to freely bend (Van Slewen, 2007). By not allowing the head of the femur to sit in the socket, the socket often does not develop properly, causing Developmental Dysplasia of the Hip or DDH (Crisholm,1983).
Carrying a young infant laying in the horizontal position with legs together in a baby carrier (like a sling or a wrap) provides adequate spinal support, but it is not the optimal position for hip development or prolonged carrying. This is especially if there is congenital dysplasia present in the infant.
The American Academy of Pediatrics released a review of swaddling under Van Slewen in 2007, which reaffirmed that infant’s legs should not be tightly swaddled. In 1965, the incidence of DDH was high in Japan when a swathing diaper was used widely by the population. The swathing diaper kept the hips together. Eight years later in 1973, Japanese doctors advised mothers to avoid “prolonged extension of the hip and knee of infants during early postnatal life”. Soon after experts reported a marked decrease in infants with DDH (Van Slewen, 2007). The International Hip Dysplasia Institute in 2012 released new information suggesting that parents avoid baby carriers that force the legs to stay together.
Harmful Hollow Back Position Due to Lack of Leg Support in Carriers
The use of cradle boards by the Native populations which also inadequately support the legs and retract the shoulders, places the spine in a compromising “hollow back” or hyper-extended position. With unsupported legs and very weak abdominal muscles the pelvis tilts back in the infant and hyper-extends his back. The infant then absorbs the pressure produced with each step that the mother takes on his hyper-extended spine. This is stressful on an infant.
The development of spondylolisthesis, the slipping of the vertebrae to compensate from repeated stress (usually on a hyper-extended spine) is pretty common in gymnasts and weight lifters. It is also unusually high in the Native Athabascan populations where nearly half may be afflicted.
Yochum and Rowe suggested that the Native Athabascans that choose to carry their infants in a cradle board may explain the high prevalence of (isthmic) spondylolisthesis in their population. Since no one has ever been born with spondylolisthesis, Yochum and Rowe dismiss the possible genetic element as the cause. Instead, they point to the cradle board (a non-physiological carrying device) as a more favorable explanation to the cause of the disease (Wong, 2004).
Although different in appearance, any modern baby carrier that does not support an infant’s legs (in a flexed abducted position oriented toward the wearer), any front facing carrier with leg holes is no more developmentally sound than a cradle board, as these carriers retract the shoulders and create the stressful “hollow back” position. Lacking proper leg support, cradle boards and front-facing baby carriers with leg holes are all very similar, pinning the shoulders back and placing pressure the base of the spine.
Supporting the Legs
Upright baby carriers that support the legs, carrying a baby as a mother would naturally would in arms, does not compromise a baby’s spine or hips (Kirkilionis, 2002). When an infant’s legs are flexed and straddled, the instinctive position that his little body assumes when picked up, the head of his femur (bone of the thigh) fills out the hip socket (acetabulum). The hip socket is filled most evenly when the legs are pulled up to roughly 100 degrees and spread roughly 40 degrees at the same time (Kirkilionis, 2002). DDH does not occur when an infant’s legs are supported. Actually this is the position that doctors advocate as treatment for babies with hip dysplasia.
Interestingly enough, babywearing is customary among the Netsilik Inuit people. Netsilik mothers don’t use cradle boards but carry their infants in their amautis of their parkas. The babies assume a seated straddling position on their mother’s back inside their coats (Montagu, 1986). No studies indicate prevalence of either DDH or spondylolisthesis in this northern Inuit baby carrying group. Their hips and spines develop normally.
A mother using either her arms or a simple piece of cloth, supports her baby’s legs in a flexed (with the knees bent) abducted (away from midline) position supporting the hip and the spine. Instead of fabric at the crotch which contributes no leg support, or swaddling the legs which is too restrictive, ergonomic carriers put the baby in the position that supports the legs just as a mother’s arms would. The flexed abducted position is what infants are hard-wired to assume when picked up. (Schon, 2007). It is what nature intended- legs spread around the mother’s hip, back or torso with knees bent in a seated position.
The fabric is pulled to the back of the baby’s knees offering proper leg support. The legs should be pulled to at least hip level for optimal positioning and proper hip development.
For a toddler, footstraps may offer tired legs a place to rest and prevent the fabric from digging into the back of his leg. With his thighs up at hip level, his back naturally rounds and subsequently takes pressure off his pelvis and lower back.
Proponents of horizontal positioning in early infancy may be concerned with whether the infant actually receives adequate levels of oxygen while being carried as compared to in a stroller. According to Dr. Maria Blois, premature infants placed in an upright position on their mother’s chests had improved respiratory patterns and are more regular than in an incubator.
Blois also reports“reduced episodes of sleep apnea (temporary cessation of breathing) and bradycardia (slowing of the heart rate). Transcutaneous oxygen levels do not decrease indicating that oxygen saturation is not compromised”. These studies were done on premature infants some weighing as little as three pounds, placed upright on their mother’s chest. The preferred position for these tiny three pound babies is upright, usually secured by a piece of cloth. They thrive upright on their mother’s chest and are almost allowed to leave the hospital earlier than little preemies left in incubators.(Blois,72). If the upright position is the preferred position for a three pound preemie, it doesn’t make sense that it could be harmful to a newborn.
Preventing Ear Infections
Lying horizontally is not only a poor option for your baby’s spine, hips, and cranium, it can also be a major contributing factor inner ear infections in infants. Gastric reflux of contents into the middle ear causes ear infections. Gastroesophageal reflux disease or GERD can be pretty prevalent in infants as sphincters tend to take a while to fully close.
Parents of infants diagnosed with GERD are advised to be carried upright to ease the symptoms. When infants are placed lying in the horizontal position, not only are the symptoms exacerbated, but gastric juices can enter the immature Eustachian tubes easier making reflux from the throat into the middle ear more probable. The same may occur when bottle fed infants are fed positioned flat on their backs and not slightly upright as milk may enter into the middle ear. A slight upright tilt prevents milk from entering into the middle ear.
The build up in the Eustachian tube can cause inflammation and a buildup of bacteria and subsequently an infection. Wearing your baby upright can actually be a preventative measure against ear infections and can help ease the symptoms of GERD (Schon, 2007).
Another benefit of carrying your baby is that carried babies receive a lot of vestibular stimulation whereas lying babies do not. Our vestibular system helps us out with our sense of balance and our security in space. When a mother holds her baby, the baby moves back and forth with mom’s walking and side to side from her swaying or rocking. Mom may stop and turn and reach to grab something or she may moves gently smoothly. These varied movements force her baby to respond appropriately to keep himself balanced. All of these movements tune her baby’s vestibular system.
When pushed in a stroller the movement is either forward or backward planar movement and not very varied. When changed from the upright position and the containment of his mother’s arms to the horizontal position laying down uncontained a baby may produce random movements and suddenly flail his arms and legs as if to save himself from falling. This is called a baby’s Moro Reflex. It acts as a baby’s primitive fight/flight reaction and is replaced later in life by an adult ‘startle’ reflex.
Carrying, rocking and swaying stimulate an infants’ vestibular apparatus and helps them to feel secure in space. Most babies today spend most of their day apart from their mothers in a container or in a stroller leaving them prone to vertigo, and a feeling of physical insecurity in space in general. Interestingly enough, the fear of flying and the fear of heights which plagues many of today’s adults can often be traced back to not being carried as an infant. Carried babies feel secure and are less apt to develop space related phobias. (Montagu, 1986)
Babies have reason to feel secure. They physically need to be in close contact with their mothers. They giggle and coo and drink in all of our expressions. Upright on mother they are able to view the world unobstructed from a safe place and can learn about all around them at their own pace. Not only are babies better off physically, in the upright position they are happier and calmer when held upright. In her book The Vital Touch, Dr Sharon Heller states,
“The more time that babies spend vertical, the more time that they are alert and calm. Even newborns that spend most of their time sleeping, stop crying and perk up when picked up and placed on our shoulder. Interestingly, how alert a newborn is relates to where he is. Upright in an infant seat, he is less alert than when upright in arms… Vertical positioning as optimal in infants makes perfect sense. Think of how much time our infants spend horizontal- flat on their back in a crib or a buggy. Might this affect their alertness? There’s a good chance… Researchers found that infants too young to sit independently learn more when placed in a vertical position.”(Heller, 94)
Stimulating the Senses
And what an incredibly stimulating environment. Not only can the infant learn about the world around her from all the different sights she sees, she is in the state of mind to do so. When an infant is calm but alert, that’s when all the information is allowed to permeate into his being. He finds out about the world and his place in it.
“Our body is a sensual cornucopia where smiles, aromas and laughter mingle amid undulating caresses that put the entire sensory world at our baby’s fingertips. Our baby gets tactile or cutaneous stimulation from our skin touching hers and proprioception from the pressure of her limbs flexed into our body. She gets tactile, olfactory, and gustatory stimulation if we nurse, of our milk, and vestibular stimulation from the gentle stimulation of our movements and, when held upright, from her efforts to right her head and maintain her balance. She gets visual stimulation when she looks all around her, auditory impulses as we whisper endearments, and kinesthetic stimulation as we change her to the other side… when we put our babies in a container, and especially if out of sight all of this sensory nourishment is lost.” (Heller,112)
Easier System Regulation
The mother/infant relationship actually provides physiological regulation of the infant’s autonomic system. A 1992 study showed that when an infant is taken away from his mother he experiences a “decreased heart rate, temperature decreases, sleep disturbances and EEG changes”- representing an impairment in the regulating processes of his own little body (Archer, 1992). Upon being separated from his mother, a baby’s immune system weakens. His body literally stops producing as many leukocytes. But when mother rejoins him, he strengthens again (Montagu, 1986).
Roots of Misinformation
With all the studies and the clear physical benefits of carrying a baby upright on mother’s chest it’s hard to understand a pediatrician’s ambivalence on the matter or outright scorn when his patients choose to do so. Perhaps the reason for not supporting upright carrying may be that they want to discourage mothers from “spoiling” their babies, or to prevent the mother and baby from getting too close or attached to each other.
Straying from wearing our babies may be linked to the old school of thought in which dates back to 1928, when the famous behaviorist Doctor John B. Watson published The Psychological Care of Infant and Child, setting out to change the course of humanity and make infants independent. His theory was that we were all born basically a blank slate, ignoring any evolutionary hard wiring or any inborn biological tendencies, and that in order to “form” an independent child it was necessary to prevent the newborn baby from creating dependent habits. In other words, if you hold on to your baby he will cling to you and never let go. He will be needy. Not only should you withhold from carrying your baby but cuddling, kissing and rocking him too; if you show affection, your baby will expect it.
So many of our grandparents and parents were influenced by this mechanistic train of thought, pressured by the experts to believe that if they picked up their babies when they cried that that they would create a tyrant of a child and become enslaved. Unfortunately this psychology had has a profound effect upon pediatric thinking and practice, and even pervades into conversations between mothers and doctors today. (Montagu, 1986)
Evolutionary Need for Touch
Most mothers are still pressure to carry out the harsh parenting methods that were inculcated into our grandparents and our parents. Yet, these mechanistic methods only go back so far. Anthropologist James McKenna claims that with our babies more often in a type of container than in our arms, they are at “odds with evolution”.
“Virtually all of our biochemistry and physiology are fine-tuned for the conditions of life that existed when we were hunters and gatherers, in which babies were held by their mothers,” McKenna writes. Our culture may be changing, but our evolutionary need for touch remains the same. Babies’ brains have evolved to expect closeness and proximity-to be held-for their safety, their psychological growth, physical growth, mental growth, to aid and stabilize their physiological processes and keep their immune systems strong” (Field, 69-74). “Touch is not an emotional fringe benefit. It’s as necessary as the air we breathe” (Heller, 5)
Making Strollers The Exception
Even though most Western parents cannot conceive of life without a stroller, they are not as gentle on an infant to as we assume them to be. Placing an infant alone on his back for long periods of time is not what we as humans are hard-wired to expect. Lying horizontally in early infancy is not easier or less stressful on an infant’s spines, skulls, or necks. Upright on mother’s body, mom adjusts to all her baby’s movements, and he to hers, moving like perfect dance partners. The two create a rhythm together, physically, and psychologically and move together in sync. Even the most state of the art strollers can’t provide the warmth that a mother’s body does, her comforting smell, the varied movement, and the sensitive motherly responses that are so essential to her baby’s healthy growth and development, especially during such a critical period when his brain is growing more than any period in his life. No toys can match the joy that an infant gets from his mother’s face. Alone, gazing up at a fabric liner with which the manufacturer chose to line the stroller is no comparison to the rich environment he witnesses and observes himself when he moves together through the day with his mother.
Strollers are not “bad” per se. To go further, babywearing and strollers need not be mutually exclusive as long as an infant is content and his cues are responded to when he signals that he needs to be held (seated and facing his mother is preferable to encourage interactions and communication) (Zeedyk, 2008).
Laying babies flat on their backs in a stroller is actually not easier on their necks, spines, hips, or their minds. Nature intended for babies to be carried. Upright positioning with proper leg support is the preferable position for your infant and is gentle enough not to physically stress even tiny three pound babies. A mother should trust what her heart tells her heart. By holding baby close to her heart she will not only be choosing the most beneficial and physically supportive method of bringing baby along with her, she will be providing the optimal environment for his psychological and emotional growth as well.
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