The aims of this study were: 1) to study the characteristics of birth and neonatal mortality (NM) rates of twins as compared to singletons in recent years in Italy; 2) to evaluate NM rate differences among twins and singletons by birthweight: 3) to calculate the cause-specific NM rates among singletons and twins. Data concerning all live-born infants were obtained from the birth and death records of the Italian Institute of Statistics (ISTAT) for the years 1981, 1985, 1989 and 1990 and were analyzed by the Statistics Office of the Italian National Institute of Health. Between 1981 and 1990 the incidence of twins increased from 18.3 to 19.1 per thousand livebirths. This increase was mainly related to twins resulting from multiple pregnancies, thus, the proportion of twins weighing < 1500g also increased from 67 to 77 per thousand. Twins accounted for 10% of overall neonatal mortality in 1981 and 14% in 1990. Between 1981 and 1990 in the Centre-South of Italy the crude NM rates showed a greater decrease among singletons than among twins, while in the North the decrement involved both singletons and twins. The birthweight-specific NM rate showed a steady improvement in survival for twins rather than for singletons in the 1500-2499g weight range. Taking each cause of death in 1989-90, NM rates were considerably higher for twins compared to singletons, Twin mortality risks due to newborn respiratory distress syndrome (RDS) and asphyxia were respectively 11 and 8 times that of singletons. The comparison between twin NM rates in the three geografical areas and in relation to the cause of death indicated a greater incidence of RDS and asphyxia in the Centre-South than in the North.
This study offers indications on the planning of perinatal care in order to improve twin survival in the Centre and South of Italy, particularly with regard to the prevention and care of asphyxia-RDS.