The American Academy of Pediatrics (AAP) recently released a joint statement with other professional organizations to promote “hip-healthy swaddling.” http://aapnews.aappublications.org/content/32/9/11.1.full
Swaddling has been long known to have many benefits for babies and has recently grown in popularity throughout the U.S. However, there have also been many concerns about hip dysplasia raised in some cultures that practice certain very tight swaddling techniques.
Hip dysplasia is a common developmental disorder in babies where excess movement at the hip socket can lead to long term consequences. Many experts believe that keeping the hips fully extended in a tight, straight-legged swaddle can exacerbate this problem.
The AAP is recommending that families emphasize tight wrapping of the upper extremities while allowing room for infants to flex their hips and knees. A video of this technique, and more information, may be found here:
http://www.hipdysplasia.org/Developmental-Dysplasia-Of-The-Hip/Hip-Healthy-Swaddling/Default.aspx