Mortality and morbidity in very preterm infants in Switzerland spanning 16 years (2006-2021).

OBJECTIVE

To report population-based gestational age (GA) stratified mortality and morbidity for very preterm infants spanning 16 years in Switzerland.

DESIGN

Swiss population-based study with prospectively collected data for infants born at less than 32 weeks GA, spanning three time periods: 2006-2011 (P1), 2012-2016 (P2), 2017-2021 (P3).

SETTING

The Swiss Neonatal Network, covering all Level III neonatal intensive care units (NICUs) and affiliated paediatric hospitals.

POPULATION: Preterm live-born infants (12 453) less than 32 weeks GA.

MAIN OUTCOME MEASURES: Trends in GA-related mortality, survival without major complications and short-term morbidities among very preterm infants in Switzerland.

RESULTS

Overall survival increased significantly from 85.4% in P1 to 89.7% in P3 (p<0.01), with greatest gains among infants born before 26 weeks GA. Delivery room and NICU mortality declined significantly, from 6.0% to 4.1% and from 8.6% to 6.2%, respectively.Survival without major complications-such as bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH), necrotising enterocolitis (NEC), retinopathy of prematurity (ROP) and cystic periventricular leukomalacia (cPVL)-remained stable (around 72%). Major morbidities occurred in 17.3% of survivors.Among survivors, BPD and ROP significantly increased across periods while NEC increased only in infants born at 25 weeks GA. Conversely, cPVL declined over time.

CONCLUSIONS

The survival rate of very preterm infants in Switzerland increased from 2006 to 2021, especially in those born before 26 weeks GA. Survival without major comorbidities among infants born at 23-31 weeks remained unchanged. In survivors, BPD and ROP increased over time; NEC increased only in 25-week infants.