OBJECTIVE
To investigate whether the development of late-onset refractory hypotension, referred to as late-onset circulatory collapse (LCC), was associated with an increased risk of developing cerebral palsy (CP) at 3 years of age in extremely preterm infants. 
METHOD
In this observational cohort study, infants who were born at 22 to 27 weeks of gestation from 2008 to 2012 in the Neonatal Research Network of Japan were eligible. The study population consisted of 3,474 infants (45.6% of 7,613 eligible infants) who were evaluated at 36 to 42 months of age. LCC was defined as a clinical diagnosis of LCC and the requirement of corticosteroids. We compared the neurodevelopmental outcomes between infants with and without LCC. Continuous and categorical variables were compared using Wilcoxon rank-sum test and chi-squared test, respectively. We estimated odds ratios with 95% confidence intervals for developing CP and other neurodevelopmental outcomes with and without adjustment for potential confounders using logistic regression models. Results with a p-value of < 0.05 were considered significant. 
RESULT
Among 7,613 eligible infants, 1,399 (18.4%) received the diagnosis of LCC. Infants with LCC had higher incidence of CP than those without LCC (18.0% versus 9.8%, p < 0.01). In multivariate logistic analysis, LCC was independently associated with CP (adjusted odds ratio: 1.52, 95% confidence interval: 1.13-2.04) and developmental quotient score of < 50 (1.83, 1.23-2.72).
CONCLUSION 
LCC should be recognized as one of the important complications of extremely preterm infants because it may be associated with CP.