Objective: The objective of this study was to obtain an accurate register of the deaths of children less than one year of age in order to discover the real infant mortality (IM) rate in Navara and its trend during the period between 1985 and 1996, a well as to investigate the deaths by sudden infant death (SID) in the same period and their relationship to the prone position during sleep.
Patients and methods: Infant mortality was determined by detailed examination of all certified deaths. Research into possible nonregistered deaths was also carried-out. The sources of information included the archives and registers of the pediatric and obstetric wards and pathology departments of all hospitals. Deaths codified as 798.0 (CIE9 infinity R) were included in the study as death by SID. To determine sleeping posture. In the second semester of 1996, a survey was carried out on a sample of 285 children of under 6 months of age. The survey's model is the same as that published previously.
Results: In the period of 1985 to 1992, IM was 12.33 per thousand live births. The SID rate was 1.30/1,000 live births. The prevalence of the prone position is unknown. In the period between 1993 and 1996, IM decreased to 5.84/1,000 live births and this decrease was proportional in both the neonatal and postneonatal components. The rate of SIM decreased to 0.44/1,000 live births. At the beginning of 1993, 86% of the children slept in the prone position, in 1994, 38% and in 1996, only 23%.
Conclusions: Trustworthy data in Navarra shows a decrease in IM of more than 50% from 1993 on. The SID rate also decreased by 65%, coinciding with a massive drop in the use of the prone position during sleep.