Purpose Unintentional injury represents the leading cause of death among young children in Canada. Peaks in infant injury rates have been found to directly coincide with newly acquired developmental motor milestones, but little is known about these patterns. The current study examines: the rate and nature of injury-risk behaviours during infancy; patterns in parent supervision during times when infants engage in injury-risk behaviours; and how injury-risk behaviours and parental supervision coincide with minor injuries sustained in infancy.

Methods Using a multi-method approach (diary forms, interviews), parents of typically-developing infants were asked to document the rate and nature of infants’ engagement in injury-risk behaviours, and injuries sustained at sitting, crawling, and walking stages. Parental supervision patterns were also examined.

Results The majority (<90%) of infants engaged in injury-risk behaviours and sustained minor in-home injuries, with the crawling stage of motor development posing the greatest injury-risk to infants. Not surprisingly, infants who engaged in more injury-risk behaviours sustained more injuries. Examining supervision patterns over developmental stages revealed that caregivers failed to increase supervision levels during crawling, even though infants were moving further and faster (i.e., able to access more hazards) in comparison to when sitting.

Conclusion Parents’ current safety practices are insufficient for managing injury threats to infants, especially as they become more mobile. Educating parents about the type of risk behaviours that lead to injury and how these change with motor development milestones can provide a foundation for them to understand the steps to be taken to prevent injuries as infants develop.

Contribution This study is the first to examine injury as a function of motor milestone, rather than age. It provides unique insight into the nature of behaviours that result in injury and how these change with motor development. This can inform our identification of developmentally-focused prevention strategies.