Swaddling Bad for the Hips?

Pity the poor swaddled babe: In exchange for a good night’s sleep, he (or she) may be sacrificing joint health later in life.

A British professor and pediatric orthopedic consultant contends that infants who are swaddled are more likely to develop developmental dysplasia of the hip (DDH), a common congenital disorder. The condition can trigger late-onset osteoarthritis or damage the hip enough to warrant a replacement. Though DDH is a common disorder and often resolves itself naturally, swaddling can delay or complicate the process, argues Prof. Nicholas Clarke of University Hospital in Southampton, United Kingdom.

Clarke advises against tight swaddles, noting that forcing the hips to straighten and shift forward can cause them to become misaligned. Research has shown that hip dislocation is significantly more common in far Eastern countries where swaddling is commonly compared with places like Nigeria, where babies are carried with their legs wrapped around their mother’s waist. Rates of hip dislocation in Japan halved after the country instituted an educational program discouraging swaddling.

“‘Safe swaddling’ with appropriate devices should be promoted because it is recognised that traditional swaddling is a risk factor for DDH,” Clarke wrote in an Archives of Disease in Childhood article.

A study of swaddled rats supports Clarke’s contention: Lab rodents wrapped tightly from birth were more likely to develop hip dislocation, researchers found, and their risk increased the longer they were swaddled.

Historically, the practice of wrapping a baby tightly in a blanket with his arms restrained and legs stretched out was almost universal until it fell out of fashion over the last few decades. But it may be making a comeback: When the Duke and Duchess of Cambridge introduced a swaddled Prince George to the world last summer, his Aden + Anais cloth wrap reportedly sold out within four hours. And demand in Britian for swaddling clothes rose 61 percent between 2010 and 2011. In North America, nine in 10 infants now are swaddled in the first six months of their lives.

Swaddling became popular due to its calming effects on infants; some evidence suggests it helps induce sleep and prevent excessive crying and colic.

Experts like Clarke are not suggesting the practice be banned altogether. Rather, he recommends parents swaddle their children loosely, in a manner that fosters natural hip development. “In order to allow for healthy hip development, legs should be able to bend up and out at the hips,” he writes in his Archives article. “This position allows for natural development of the hip joints. The babies’ legs should not be tightly wrapped in extension and pressed together.”