Control group: infants will assist at child consultations (at 2, 6 and 12 months of corrected gestational age) whit non trained neonatologists. These neonatologists will record a video that will be assessed by certifieds external evaluators. Infants in the control group won't receive the verbal intervention. However, they will receive a development stimulation guide adapted of the ministerial guides for the stimulation of development of the Ministry of Health of Chile.