Neonatal and postneonatal mortality by maternal education--a population-based study of trends in the Nordic...

This study examined changes in the educational gradients in neonatal and postneonatal mortality over a 20-year period in the four largest Nordic countries.

The study populations were all live-born singleton infants with gestational age of at least 22 weeks from 1981 to 2000 (Finland 1987-2000). Information on births and infant deaths from the Medical Birth Registries was linked to information from census statistics. Numbers of eligible live-births were: Denmark 1 179 831, Finland 834 299 (1987-2000), Norway 1 017 168 and Sweden 1 971 645. Differences in mortality between education groups were estimated as risk differences (RD), relative risks (RR) and index of inequality ratio (RII).

Overall, rates of infant mortality were in Denmark 5.9 per 1000 live-births, in Finland 4.2 (1987-2000), in Norway 5.3 and in Sweden 4.7. Overall the mortality decreased in all educational groups, and the educational level increased in the study period. The time-trends differed between neonatal and postneonatal death. For neonatal death, both the absolute and relative educational differences decreased in Finland and Sweden, increased in Denmark, whereas in Norway a decrease in absolute differences and a slight increase in relative differences occurred. For postneonatal death, the relative educational differences increased in all countries, whereas the absolute differences decreased.

All educational groups experienced a decline in infant mortality during the period under study. Still, the inverse association between maternal education and RR of postneonatal death has become more pronounced in all Nordic countries.