UPDATE: This article was written in the 1990s when the all of the popular upright baby-carrier designs had the harmful characteristics described below. Today, several new and improved upright carrier designs are available. The gold standard for carrying your baby should be your own arms. In other words, an upright carrier should hold your baby the way your arms would, e.g., facing you with legs in a frog-like, spread-squat position with the baby's weight supported across the buttocks and thighs. —Ed.
As we are finally realizing the benefits of "wearing" our infants while we perform our daily activities, we must be careful not to compromise the integrity of our child's spine through the use of improper carriers. Spondylolisthesis (specifically, Type II/isthmic) is a condition that can result from excessive stress in the low back, such as a baby's spine might experience in certain carriers on the market today. It is relatively uncommon, but when aggravated is extremely painful. This article explains which styles of baby carriers promote healthy spine development in an infant and describes the unnecessary stress and resulting spinal condition that can result from using certain carriers.