Baby Soft Carriers: Which Type is Safer —Vest or Shoulder Type?

Abstract

To examine head swings associated with the use of baby soft carriers and to highlight the need for the careful use of these products. The head motion of babies was examined using dummy babies strapped into two types each of shoulder belt- and vest-type baby carriers. The adult carrying the ‘baby’ was required to run up and down 20 stairs over a period of 10s. A red circle marker was placed on the lateral angle of the baby's eye, with another marker placed on the backboard of the baby carrier. The motion of the baby's head was recorded using a portable video camera attached to the baby carrier and connected to a digital video recorder. The recording captured 30frames/s. Two-dimensional spatial coordinates of the selected points were calculated using direct linear transformation. Side directional and vertical swings were analyzed separately for upstairs and downstairs movement. Because the position between the video camera and the ‘baby’ was kept constant, differences in head swings between the different carriers could be evaluated by counting the number of pixels. Both shoulder-type baby carriers evaluated in the present study resulted in less head swing compared with the vest-type carriers. Regardless of whether the adult was running up or down the stairs, the side swing of the baby's head was significantly greater than the vertical swing. We recommend that shoulder belt-type baby carriers are used in preference over vest-type carriers and that adults carrying babies move slowly, especially when climbing stairs.