Countries in Europe seems to host the most pediatricians who recommend that babies should lay flat on their backs in a stroller in early infancy and not be carried due to avoid pressure on their underdeveloped bodies. Yet, laying a young infant on his back alone in a stroller is actually stressful both physically and emotionally and can be developmentally inhibiting. Being carried or worn in an upright position with proper leg support is not only developmentally sound but the preferable way to bring the baby along with you throughout your day. Upright carrying optimizes the physical, emotional and intellectual growth of your baby.
Our spine is not perfectly straight, even though it may appear so when looking at someone from the front or the 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. "They are formed as a consequence of adaptation to the external environment (gravity)"(Morningstar, 2005). 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 spine of an infant is C-shaped (a convex curve). He has neither the balancing curves nor the strength to his head upright.
First Several Months
As your infant works against gravity his muscles start to develop. Strong neck muscles help an infant hold up a heavy head forming the neck (cervical) curve of the spine.
Six Months to One Year
As an infant learns to crawl and stand, the lower back (lumbar) curve and his muscles develop so that he can stand upright. When he walks away from you on his own, only then are all of his curves developed.
As shown above an infant's c-shaped spine doesn't stretch out immediately after birth. On the contrary, the s-shape of the spine is not fully developed until he starts to walk on his own. Laying your young infant flat on his back is not gentle on his spine. In fact, it is stretching the c-curved spine into a straight line. It is actually stressing the infant's spine instead of supporting its 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).
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)".
Plagiocephaly in an infant corrected by helmet to reshape her head.
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)
Sometimes containers may help us out for short periods of time and free our hands. Yet, no container can replace a mother's arms.
*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.
Newborns are virtually 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 and they digest their food better. It is also the best position for thermoregulation because of reduced stomach exposure. 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.
By holding your baby with his knees flexed flat against your chest and supporting the his bottom you are supporting your baby in the natural position that his body instinctively assumes to ensure that he is comfortable, warm and safe.
If the stroller positions the baby in a somewhat upright position (like in infant car-seats) it may be gentler on the baby's c-shaped spine in that it is not stretching it flat. However, although it may seem like gentler option for transporting your little one around, research by the International Chiropractic Pediatric Association shows that car seats are not the ideal transport for your infant due to "restricted postural options which can impact your baby's developing cranium and spine" (International Chiropractic Pediatric Association).
By keeping and maintaining 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.
This baby is enjoying a nap outside near the peonies. Although the car seat does support her spine and head and neck while she is napping, when she is awake the straps prevent her from working her muscles to hold up her own head. Many babies spend most of their waking hours in restrictive seats like these.
When infants are held upright, however, they are allowed to practice compensatory movements enhancing muscular strength and allow them 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.
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, leaving babies to dangle from the crotch due to complete lack of leg support. Perhaps they have seen so many babies facing out when carried upright that they assume all upright carrying is nonsupportive.
It may be that the studies of the Inuit's and their high prevalence of spondlylolisthesis or the Navajo Indians and their high prevalence of developmental dysplasia of the hip (DDH) is enough evidence from babywearing cultures to close the book- deem all upright baby carriers harmful-and recommend strollers as a safer option of transport.
The images above are perhaps the carriers that many doctors imagine and classify as unsafe or harmful. Both are nonpysiological carrying devices. These 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 nonphysiological 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 mother and his bottom was seated in it. Instead the baby's spine is straightened and often hyperextended (concave "hollow back" shaped) due to weak abdominal muscles and lack of leg support.
When an infant is carried in a baby carrier he should be oriented toward the mother and ideally the fabric should extend to the back of the knee to adequately support the legs, which in turn positions the pelvis, and then supports the spine properly. 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.
Although there is a myriad of 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, 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, due to forced straightening of the legs, the socket often did not develop properly causing Developmental Dysplasia of the Hip or DDH (Crisholm,1983).
Although carrying your young infant laying in the horizontal position with legs together in a baby carrier (like a sling or a wrap) provides adequate spinal support, it is not the optimal nor the preferred position for hip development or prolonged carrying, 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 that reaffirmed that infant's legs should not be tightly swaddled. In 1965, the incidence of DDH (developmental dysplasia of the hip) was high in Japan when a swathing diaper was used widely by the population. The swathing diaper kept the hips together. However eight years later in 1973, 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).
Babies love to be contained and enclosed but straightening their legs goes against their instinctual position of flexed widespread legs. This baby is swaddled so that the legs are wrapped loosely and not forcefully straightened.
The Inuit's use of papooses, 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. Taking in the pressure produced with each step the mother takes on his hyper-extended spine 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 Inuit and Athabascan populations- where nearly half may be afflicted.
Yochum and Rowe suggested that the Eskimos, who carry their infants in a papoose, place undue amount of premature stress on the pars (part of the vertebrae) and explains 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 favoring the papoose (a nonphysiological 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 papoose, as these carriers retract the shoulders and create the stressful "hollow back" position. Lacking proper leg support infant biomechanics when worn in papooses, cradle boards and front-facing baby carriers with leg holes are very similar, pinning the shoulders back and placing the entire child's weight on his crotch or the base of the spine.
Upright baby carriers that support the legs carry a baby as a mother would naturally would in arms do 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 the Netsilik Eskimos who are big babywearers don't use papooses but carry their infants in their amautis of their parkas. They assume a seated straddling position on their mother's back inside their coats (Montagu, 1986). There have been no studies indicating prevalence of either DDH or spondylolisthesis in this northern Eskimo baby carrying group. Their hips and spines develop normally.
This baby's spine, hips, and legs are supported.
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.
A mother's arms support the baby's bottom and legs. Subsequently, pressure is taken off the spine and the weight of the baby is evenly distributed in an ergonomic 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.
The photo on right shows proper spine position, oriented toward mother, proper leg support, proper head/neck support.