Following the exponential increase in the survival rates of premature infants, recent follow-up studies suggest that this population peristresshas neurodevelopmental disabilities and three times greater risk of developing mental disorder. Several studies supporting the perinatal events have harmful effects due to their dysregulative effect on baby's nervous system. Further studies are necessary to examine the perinatal factors in order to achieve the same survival rates with minor consequences and disability. This project aims to study the influence of risk factors and protection factors, in terms of both biological features (neuroendocrine; gene expression, and polymorphisms) and environmental features (the mother's psychopathology and the psychopathology associated motherhood, mother-son interaction, family environment and social support) on infant temperament, especially on emotional dysregulation, which is considered an initially vague but tangential syndrome to many mental disorders during early childhood.