 Sample size The sample size of the cohort is based on the original RCT design.INIS Study Collaborative Group 2008, INIS Collaborative Group 2011 For the purpose of this secondary analysis the cohort may thus be considered a convenience sample. To the best of the investigators knowledge this cohort is the second largest to evaluate neurodevelopmental outcomes following neonatal sepsis.Alshaikh 2013 In multivariate analyses of 6093 extremely-low-birth-weight ELBW infants from the National Institute of Child Health and Human Development NICHD cohort followed up at two years of age, Stoll and colleagues were able to demonstrate clinically relevant differences OR 1.3 in key neurodevelopmental outcomes between uninfected babies and different categories of babies with neonatal sepsis with statistical significance.Stoll 2004 The same accounted for their subgroup analyses according to causative organism.Stoll 2004 In much smaller studies, others have also demonstrated statistically significant impact of neonatal sepsis on neurodevelopmental outcome, as reviewed elsewhere.Alshaikh 2013 The investigators therefore expect the INIS cohort to have sufficient power to detect clinically relevant differences OR 1.3 in neurodevelopmental outcomes between VLBW infants with suspected versus proven neonatal sepsis. 