[Determinants of perinatal and infant mortality in Italy 1980-1983].

Determinants of stillbirth, perinatal and infant mortality in Italy have been analyzed using information collected routinely by the Italian Central Institute of Statistics on more than 2,400,000 births and 33,000 infant deaths in the period 1980-1983. Individual records include data on maternal (for example age, education, obstetric history) and fetal (sex, birth weight, gestational week at birth) characteristics. The Italian stillbirth, perinatal and infant (1st-365th day of life) mortality rates were respectively 7.7/1000 births, 16.4/1000 births and 13.5/1000 livebirths for the considered period. Perinatal and infant mortality was impressive in very low birth weight. About 90% of livebirths weighing less than 1000g died within the first year of life, but this percentage decreased to about 45% in babies weighing 1000-1499g. As a whole, low birth weight explained more than 70% of deaths. Further, stillbirth, perinatal and infant mortality rates were higher in male babies, in older women and in higher birth rank. These findings persist, although less markedly, after adjustment for weight. Mortality rates were about 60-70% higher in less educated women. Stillbirth, perinatal and infant mortality rates were 20 to 30% higher in Southern Italy, as compared to the North of the country. This finding was not markedly changed after adjustment for birth weight and maternal age and education, suggesting that socio-economic factors are per se important determinants of perinatal and infant mortality in Italy, and explain in terms of population attributable risk, about 15% of stillbirths or deaths within the first year of life.