0-6 months
Carrying your baby tummy to tummy is a position where the baby is held in a crouched position and is the most adequate method for carrying a newborn at least up to the age of 4 months. Your baby's back is kept well-rounded, as if still in the womb, while his knees are pulled upwards and his feet pointing down. This position is the same as when practicing skin-to-skin with your baby, which becomes possible as soon as he weighs at least 8 pounds, safely and easily. This crouched position will give him the comfort necessary to his sense of emotional security and is known to be beneficial to the development of his bones and joints. Before the age of 6 months, applying tension in the middle of the baby's back needs to be avoided. When using the horizontal extension, make sure not to tighten the straps too much. Use the support cushion to properly position the baby from 8lbs to 12lbs (3,6 to 5,5kg).
6 months and up
Starting at 6 months, when your baby can sit by himself, his spine is sturdy enough to no longer need constant back support. When he is tall enough, the support cushion will no longer be needed and he will even be able to have his arms out above the shoulder straps.