Background: Despite the technological and medical advances in perinatal and neonatal care, the rate of preterm birth continues to rise and contribute to the increased costs to the health care systems worldwide. Neonatal clinicians often find themselves trying to determine what neonatal factors are more influential in determining the prognosis of a positive or adverse outcome in this high-risk population. Objective: The objective of this study was to: 1) to identify neonatal clinical milestones and determine their predictive value for a positive neurodevelopmental outcome; and 2) to determine the individual and combined prognostic effects of these events on the neurodevelopmental outcomes of high risk preterm infants. 

Method: Neonatal and neurodevelopmental followup data from 437 extremely preterm infants were analyzed in a logistic regression model. The results of the logistic regression models were then validated using bootstrap sampling methods. Specifically, 1000 bootstrap replications of size 400 were selected from the sample and each replication was run replication was run through a logistic regression model. Variables that came out significant in greater than 50% of the 1000 models were considered to have been validated. 

Results: In the model, age at which all positive pressure for respiratory support was found to be significant, OR=2.17. 95% CI=1.15-4.11 (p=0.0.18); as well, the need for oxygen support at 36 weeks gestation, OR=0.57. 95% CI=0.33-0.99 (p=0.045); and the presence of periventricular echogenicity, OR=0.23. 95% CI=0.057-0.95 (p=0.043).Both age at which all positive pressure for respiratory support and periventricular echogenicity were found to be significant in more than 50% of simulations (71.1 and 57.0% respectively), with the need of oxygen support at 36 weeks gestation in just under 50% (47.2) . There was no interactive or cumulative effect between the three variables.

Conclusion: Extremely preterm infants who spent less time on any form of positive pressure ventilatory support were more likely to experience a positive neurocognitive outcome. Similarly, those infants who showed no evidence of injury to brain white matter  had an increased likelihood of experiencing a positive neurocognitive outcome but not as high as positive pressure ventilatory support. Utilizing the information from this study once supported and validated by additional studies will assist clinicians in their counselling with parents of these infants during their time in the neonatal care setting.