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Neonatal intensive care unit occupancy rate and probability of discharge of very preterm infants



To assess the association of NICU occupancy with probability of discharge and length of stay (LOS) among infants born <33 weeks gestational age (GA).

Study design

Retrospective study of 3388 infants born 23–32 weeks GA, admitted to five Level 3/4 NICUs (2014-2018) and discharged alive. Standardized ratios of observed-to-expected number of discharges were calculated for each quintile of unit occupancy. Multivariable linear regression models were used to assess the association between occupancy and LOS.


At the lowest unit occupancy quintiles (Q1 and Q2), infants were 12% and 11% less likely to be discharged compared to the expected number. At the highest unit occupancy quintile (Q5), infants were 20% more likely to be discharged. Highest occupancy (Q5) was also associated with a 4.7-day (95% CI 1.7, 7.7) reduction in LOS compared Q1.


NICU occupancy was associated with likelihood of discharge and LOS among infants born <33 weeks GA.

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Fig. 1: Standardized ratios for probability of discharge according to NICU occupancy quintiles.
Fig. 2: Standardized ratios for probability of discharge by NICU occupancy quintile stratified according to discharge destination.

Data availability

Data for this study cannot be shared publicly as it is bound by confidentiality agreements governed by hospital and government privacy offices. Aggregate data may be made available from the corresponding author [MB] on reasonable request.


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The authors gratefully acknowledge all site investigators and abstractors of the Canadian Neonatal Network. We also thank the staff at the Maternal-Infant Care (MiCare) Research Centre at Mount Sinai Hospital, Toronto, ON for organizational support of the Canadian Neonatal Network.


MB holds an Early Career Investigator Grant from the CIHR Institute of Human Development, Child and Youth Health (IHDCYH), a Research Grant Funding from the FRSQ Clinical Research Scholar Career Award Junior 1, and an Early Career Investigator Grant from the Montreal Children’s Hospital Foundation.

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Authors and Affiliations




MB conceptualized and designed the study, drafted the manuscript, and adjusted the manuscript according to the comments of co-authors. SP collected and analyzed the data, contributed to study design and critically reviewed the manuscript. AL, SM, VB and BP provided administrative support for data access. ES, GL, AL, STD, SM, VB and BP provided review and critical appraisal of the manuscript.

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Correspondence to Marc Beltempo.

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Beltempo, M., Sargi, E., Patel, S. et al. Neonatal intensive care unit occupancy rate and probability of discharge of very preterm infants. J Perinatol (2023).

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