Many parents believe one way to soothe a colicky newborn or lull a small baby to sleep is by swaddling, the practice of neatly binding a baby in a blanket with arms restrained and legs extended. New research shows that this practice may be harmful to a child, potentially causing developmental dysplasia of the hip.
"There has been a recent resurgence of swaddling,” Professor Nicholas Clarke, of Southampton University Hospital, wrote in an article published in Archives of Disease in Childhood earlier this month. "In order to allow for healthy hip development, legs should be able to bend up and out at the hips. This position allows for natural development of the hip joints.”
Swaddling has been around at the very least since the days of the Holy Bible, judging from descriptions in the New Testament. Throughout time, it has been practiced across all classes of various societies, from nomadic herders of yesteryear to contemporary English royalty as recent photos of baby George attest. Although swaddling is avoided in hot climates where mothers generally prefer a sling, a few centuries ago, swaddling was common practice in “most societies of the north temperate and subarctic regions, in the Mediterranean and Middle East areas, in Asia and South America, and many other parts of the world,” wrote the authors of a 2007 review of swaddling published in Pediatrics.
Scientific studies aside, sleepless parents far and wide have 'empirically' discovered swaddling reduces crying. In fact, the authors of "Swaddling: A Systematic Review" support this view: “It is clear that swaddling stimulates sleep continuity.” The researchers also noted how the practice calms infants and induces sleep, working better than massage in reducing crying symptoms even among infants with cerebral damage. Unfortunately, though, upon systematic examination of various published studies, they discovered associated risks of developing overheating, sudden infant death syndrome, and hip dysplasia. For these reasons, the researchers concluded the practice, despite its ability to lull babies to sleep, could not be recommended.
Judging from the recent revival of this custom, their warning clearly was not heeded. Today, others have begun to sound the alarm.
The American Academy of Orthopedic Surgeons describes the hip as a "ball-and-socket" joint in which the ball fits firmly into the socket when normal. In babies and children with developmental dysplasia (dislocation) of the hip (DDH), the ball is loose in the socket and may be easy to dislocate. Most often, DDH is present at birth, but it may also develop during a child's first year of life. Commenting on the association of swaddling with DDH, Clarke, a pediatric orthopedic surgeon, noted, “The babies' legs should not be tightly wrapped in extension and pressed together." In his article, he describes how swaddling potentially forces the hips to straighten and shift forward unnaturally, which could cause misalignment. In turn, this potentially could lead to problems later in life. Osteoarthritis and hip replacement in middle age are among the health scares he raised.
Significantly, he is not alone. In her recent article published in American Journal of Human Biology, Samantha H. Blatt, Ph.D., of the anthropology department at Boise State University, explores the prevalence of DDH among indigenous peoples of North America. Noting that clinical prevalence of DDH is the highest among modern indigenous populations, she performed a systematic study of the paleoepidemiology — an investigation of the ancient origins of this condition — among this group.
To conduct a study, she examined the pelves of 390 adults from the Late Prehistoric Buffalo site, West Virginia, to see if they showed signs of DDH. For each, she examined any changes in the pelvis, lower limb, and spine, as well as cranial deformation, to uncover evidence of infant restriction. Next, she calculated and compared the prevalence of DDH among living and archaeological indigenous peoples. In total, Blatt identified DDH in 18 adults, leading her to conclude that indigenous peoples of North America have the highest reported global prevalence of DDH not only today, but also in prehistory.
“The etiology of DDH suggests that components of both genetic predisposition and swaddling practices have combined to create a high-risk environment for the development of DDH, contributing to its high prevalence within archaeological populations, like Buffalo, and modern Native American/Aboriginal groups within North America,” she wrote. Perhaps some customs, despite their emotional pull, are best left to the past.
Sources: Blatt SH. Joined at the hip? A paleoepidemiological study of developmental dysplasia of the hip and its relation to swaddling practices among indigenous peoples of North America. American Journal of Human Biology. 2013.
Clarke NMP. Swaddling and hip dysplasia: an orthopaedic perspective. Archives of Disease in Childhood. 2013.
Van Sleuwen BE, Engelberts AC, Boere-Boonekamp MM, et al. Swaddling: A Systematic Review. Pediatrics. 2007.