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 follow
up 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.