Objective: to analyze neonatal mortality by cause using the P-Perinatal classification system of the Italian National Institute of Statistics (ISTAT).
Design: comparisons by birth cohort (1991-2001 vs 1981-1990). Estimates of the rate ratio (RR) and 95% confidence intervals (CI). The 56 ISTAT causes of perinatal death were regrouped into 7 categories.
Setting: the study was carried out in the Campania region, which has the largest number of births in southern Italy and high neonatal mortality. The analysis covered 1627641 live births and 12865 neonatal deaths.
Results: neonatal mortality declined significantly over time (RR= 0.58; 95% CI 0.56-0.60). The decrease was greater for early (first 6 days of lfe) (RR=0.54; 95% CI 0.51-0.56) than for late neonatal mortality (6th to 29th day of life) (RR=0.75; 95% CI 0.69-0.81). Rates declined for all causes, but RR were particularly low for prematurity (RR=0.24; 95% CI 0.22-0.28), pre-partum hypoxia (RR=0.28; 95% CI 0.22-0.35), intra-partum hypoxia (RR=0.42; 95% CI 0.38-0.47). More limited declines were observed for congenital anomalies (RR=-0.67; 95% CI 0.61-0.72) and for RDS (Respiratory Distress Syndrome) (RR=0.82; 95% CI 0.77-0.87). Declines inpre- and intra-partum hypoxia and for other causes were observed in both early and late neonatal mortality. Mortality due to congenital abnormalities declined more in the early neonatal period (RR=0.59; 95% CI 0.53-0.65) than in the late neonatal period (RR=0.86; 95% CI 0.75-0.99). RDS, which was the leading cause of death in both periods, was the only cause for which there was an increase in late neonatal mortality (RR= 1.21; 95% CI 1.05-1.40).
Conclusion: Available current data allow to describe different determinants of neonatal mortality by causes of death. Currently, improvement of RDS care is necessary in order to reduce high neonatal mortality.