Risk / Survival Analysis / Treatment Outcome / Birth Weight / Pregnancy / Humans / Female / Male / New Zealand / Infant / Newborn Infant / Public health systems and services research / Retinopathy of prematurity / Neonatal Intensive Care Unit / Gestational Age / Cerebral Hemorrhage / Humans / Female / Male / New Zealand / Infant / Newborn Infant / Public health systems and services research / Retinopathy of prematurity / Neonatal Intensive Care Unit / Gestational Age / Cerebral Hemorrhage