Open Access Research article

Outcome at two years of age in a Swiss national cohort of extremely preterm infants born between 2000 and 2008

Luregn J Schlapbach12, Mark Adams3, Elena Proietti4, Maude Aebischer5, Sebastian Grunt6, Cristina Borradori-Tolsa7, Myriam Bickle-Graz8, Hans Ulrich Bucher3, Beatrice Latal9, Giancarlo Natalucci39* and for the Swiss Neonatal Network & Follow-up Group

Author Affiliations

1 Neonatal and Paediatric Intensive Care Unit, Department of Paediatrics, University of Bern, Bern, Switzerland

2 Paediatric Critical Care Research Group, Mater Children’s Hospital, Brisbane, Australia

3 Department of Neonatology, University Hospital Zurich, Zurich, Switzerland

4 Division of Pediatric Pneumology, University Children Hospital, Bern, Switzerland

5 Division of Neonatology, Department of Paediatrics, University of Bern, Bern, Switzerland

6 Division of Neuropaediatrics, Development and Rehabilitation, University Children’s Hospital, Berne, Switzerland

7 Department of Paediatrics, Geneva University Hospital, Geneva, Switzerland

8 Division of Neonatology, Department of Paediatrics, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland

9 Child Development Centre, University Children’s Hospital Zurich, Zurich, Switzerland

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BMC Pediatrics 2012, 12:198  doi:10.1186/1471-2431-12-198

Published: 28 December 2012



While survival rates of extremely preterm infants have improved over the last decades, the incidence of neurodevelopmental disability (ND) in survivors remains high. Representative current data on the severity of disability and of risk factors associated with poor outcome in this growing population are necessary for clinical guidance and parent counselling.


Prospective longitudinal multicentre cohort study of preterm infants born in Switzerland between 240/7 and 276/7 weeks gestational age during 2000–2008. Mortality, adverse outcome (death or severe ND) at two years, and predictors for poor outcome were analysed using multilevel multivariate logistic regression. Neurodevelopment was assessed using Bayley Scales of Infant Development II. Cerebral palsy was graded after the Gross Motor Function Classification System.


Of 1266 live born infants, 422 (33%) died. Follow-up information was available for 684 (81%) survivors: 440 (64%) showed favourable outcome, 166 (24%) moderate ND, and 78 (11%) severe ND. At birth, lower gestational age, intrauterine growth restriction and absence of antenatal corticosteroids were associated with mortality and adverse outcome (p < 0.001). At 360/7 weeks postmenstrual age, bronchopulmonary dysplasia, major brain injury and retinopathy of prematurity were the main predictors for adverse outcome (p < 0.05). Survival without moderate or severe ND increased from 27% to 39% during the observation period (p = 0.02).


In this recent Swiss national cohort study of extremely preterm infants, neonatal mortality was determined by gestational age, birth weight, and antenatal corticosteroids while neurodevelopmental outcome was determined by the major neonatal morbidities. We observed an increase of survival without moderate or severe disability.

Development; Disability; Mortality; Outcome; Preterm