Epipage 2 (epidemiologic study on small-for-gestational-age children) is a nationwide study implemented to improve our knowledge of the outcome of preterm children in France. This study was launched on March 28, 2011 and includes three groups of preterm children, all born before 35 weeks: extremely preterm infants (born between 22 and 26 completed weeks of gestation), very preterm children (born between 27 and 31 completed weeks) and moderately preterm children (born between 32 and 34 completed weeks).

These children are being studied from their birth up to the age of 12 years. At birth, data on maternal and infants' characteristics were collected from medical records. At one and two years, questionnaires sent to families and to physicians (at two years only) allowed to collect data about the children's life and health.

At five and a half years, medical and psychological assessments are specifically implemented for the study in order to evaluate motor and cognitive disorders in this population.

Inclusion Criteria:

• initially included in EPIPAGE 2 cohort or complementary studies or Elfe cohort study
• family agreement to participate to cohort follow up
• informed consent form signed by both parents
• affiliated to social security system

Exclusion Criteria:

• parental refusal
• not affiliated to any social security system

Preterm children included at birth in the EPIPAGE 2 cohort or in complementary studies whose famillies agree to participate to EPIPAGE 2 follow up (4600 children) + 600 children born at term and participating to the Elfe cohort (French longitudinal study of children)