Testing standards, which regulate design of child restraint systems (CRS), have set upper weight limits for children. However, there is no regulation on the lower weight limit. CRS manufacturers generally recommend a 5 pound lower weight limit, which creates a challenge for premature infants who often weight less than 5 pounds. The specific aim of this study is to collect and analyze anthropometric dimensions across a range of low birth weight and premature infants at time of hospital discharge relevant for optimal CRS design.