What height should I set my crib's mattress support at?
Generally, the highest level is for newborns. Once your baby can roll over, sit up, or push up onto their hands and knees, the mattress support should be lowered. The higher levels make it easier to take your infant out of the crib, but they're dangerous when your child is able to pull themselves to a standing position.
The mattress support's level should be lowered as your baby grows. It should always be set to a level where they cannot climb out. By the time your child is able to pull to a standing position, the support should be at its lowest setting..
Once your child begins to climb or reaches 35" in height, we recommend that you cease using the crib or convert it to a toddler bed.