The age-old practice of swaddling — bundling a baby tightly in a blanket to reduce crying and promote sleep — has regained popularity in recent years. Some research suggests that 90 percent of babies in the U.S. and Canada are swaddled during their first few months.
But there’s a “right” and “wrong” way to swaddle, as a British pediatric orthopedic surgeon, Dr. Nicholas Clarke, points out in a paper published today in the Archives of Disease in Childhood. And it’s important, stresses Clarke, that parents, pediatricians, midwives and others know the difference.
That’s because swaddling the wrong way — with the baby’s legs extended and pressed together — may lead to developmental dysplasia of the hips, he says.
A common condition
Hip dysplasia, or dislocation, occurs when the bones of the hip joint do not align correctly. It’s one of the most common congenital disorders. One out of every 20 infants born full term have some kind of hip instability, according to the International Hip Dysplasia Institute.
In most cases, this instability resolves on its own — without any kind of treatment — during the baby’s first few weeks or months. That correction can become delayed, however, if the baby is repeatedly swaddled in a way that forces his or her hips to straighten and shift forward in a misalignment, says Clarke.
Developmental hip dysplasia in infancy is associated with an increased risk of osteoarthritis and hip replacement in middle age.
In Japan, where tight, straight-legged swaddling has been traditionally practiced, an educational campaign aimed at grandmothers in the 1970s resulted in a more more than fivefold reduction in the rate of hip dysplasia.
On the other hand, three Australian physicians reported in 2012 that their medical institution had experienced a recent threefold increase in the incidence of developmental hip dysplasia in young children, which the physicians suggested might be caused by a resurgence of swaddling.
Balancing the risk
“In order to allow for healthy hip development, legs should be able to bend up and out at the hips,” writes Clarke. “This position allows for natural development of the hip joints.”
“A baby does not need to be swaddled, but in some situations, it may be helpful to decrease crying and improve sleeping,” he wrote in an e-mail exchange with MinnPost. “[But] this needs to be balanced against the risk for development of hip problems.”
If parents want to swaddle, then they should “do it in a way or use one of the newer swaddling clothes/blankets to allow the hips to flex and move,” he added. “The child should not be swaddled so tightly that the legs are kept extended and not be able to move.”
Berkowtiz also pointed out, however, that the association between swaddling and hip dysplasia is “not huge.” The concern is greatest, he said, for infants with particular risk factors, most notably those who experienced a breech birth or who have a family history of hip problems.
Advocates of swaddling claim the practice simulates for the infant the calming sensation of being in the womb. Indeed, some research has shown that swaddled babies do, in general, sleep longer.
“As with lots of other practices, I am not dogmatic about the practice,” stated Berkowitz. “If a family asks if swaddling is OK, I recommend it not be too tight (specifically, loose enough to allow hip and leg movement) and make sure the infant is still sleeping on their back and their mouth/nose is not covered at all. … I use it for routine minor sleep and fussiness issues, and for some babies, it helps.”
“Safe swaddling” is an easy-to-learn technique. It simply requires providing the baby with plenty of leg room. For a demonstration, you can watch the International Hip Dysplasia Institute video below.