The i-Size standard stipulates that children up to the age of at least 15 months must be transported rear-facing in the car. A baby's head is still relatively large and heavy in relation to the rest of their body. The neck muscles and the spine are not yet sufficiently developed.
If the child is being transport in the rear-facing position of the car, the forces of the impact are transferred to the seat shell, as it encloses the entire body and head area. Thus, the sensitive head and neck area of the child is optimally protected.
In a forward-facing position, the baby’s head would be accelerated forward in an accident with great force, which could lead to the most serious injuries.