Trends in mortality and morbidity in very preterm infants in Switzerland based on the years 1996, 2000 and 2004

Objective: The purpose of this population-based study was to investigate the trends in hospitalisation duration, interventions and short-term outcome of very preterm infants from birth until discharge home.

Methods: The Swiss Minimal Neonatal Dataset took account of all infants born alive before 32 completed gestational weeks in Switzerland in 1996 (n=606), 2000 (n=675) and 2004 (n=654). A poor outcome was defined as death or survival with intracranial haemorrhage grade 3 or 4, cystic periventricular leucomalacia, ROP stage 3 or 4 or BPD (requirement for supplemental oxygen at 36 weeks postmenstrual age).

Results: Mean mechanical ventilation was 3.6 days in 1996, 2.8 days in 2000 and 2.4 days in 2004 (p<0.001). The mean days of nasal CPAP increased from 4.6 in 1996 to 9.0 in 2000 and 14.1 in 2004 (p=0.02). The mean duration of hospitalization for survivors decreased from 66.2 days in 1996 to 64.2 days in 2004 (p=0.27). Mortality (15%) and poor outcome (31%) remained stable over eight years. A comparison with the birth registry of the Swiss Federal Statistical Office revealed a increasing rate of VLBW infants: from 0.76% in 1996 to 0.86% in 2004 (p=0.03).

Conclusion: Since implementation of prenatal steroids and surfactant in Switzerland, a change of respiratory support strategy occurred. Mortality and morbidity rates remained stable even though the rate of VLBW infants increased.