Perinatal and postneonatal mortality among Indigenous and non-indigenous infants born in Western Australia, 1980-1998

Objective: To describe cause-specific perinatal and postneonatal mortality for Indigenous and non-Indigenous infants using a new classification system . Design: Total population retrospective cohort study. Participants and setting: All registered births in Western Australia of bir thweight greater than 399 g from 1980 to 1998, inclusive. Main outcome measures: Rates and time trends for all births.1980-1998, and cause-specific rates for births 1980-1993 of fetal, neonatal and postneonat al and childhood deaths. Results: For indigenous infants born 1980-1998, the mortality rate before t he first birthday was 2.7 times (95% Cl, 2.5-2.9 times) that for non-Indige nous infants. Indigenous infants born 1980-1993 had a higher mortality rate in all cause-of-death categories. The highest relative risk was for death attributable to infection (8.1; 95% Cl, 6.5-10.0) which occured primarily i n the postneonatal period; the source of the infection was less likely to b e identified in Indigenpous deaths. From 1980-1998, the rate of neonatal de aths decreased at a greaterrate for Indigenous than for non-Indigenous infa nts. However, while stillbirth and sudden infant death syndrome rates for n on-Indigenous births fell, they remained static for Indigenous births. Conclusions: The new classification system, which considers the underlying rather than immediate cause of death, enables investigation of the causes o f all deaths, from stillbirths to childbirth. This system has highlighted t he comparative importance of infection as a cause of death for Indigenous i nfants, particularly in the postneonatal period.