Study 2 The premature infant is characterized with immature muscle with a low tension and therefore, a low ability to eat its needs by breastfeeding the first period. The transfer of milk from mother to child is an interaction between the mothers and her milk ejection reflex that establish a positive pressure on the milk and the child that have to establish a vacuum. The hypothesis is that the premature infants suction power is too weak to establish sufficient intraoral vacuum to ensure milk transfer from the breast to the infant and it can be related to a fewer number of days where the infant is exclusively breastfed.