The roles of socioeconomic status and Aboriginality in birth outcomes at an urban hospital

Objectives: To explore the role of socioeconomic status and Aboriginality on birthweight at an urban hospital. Design, participants and setting: Extraction of data on the demographic characteristics (socioeconomic status, mothers' single-parent status, age and smoking status) and infants' birthweight from a clinical record system. Infants delivered at an outer urban hospital to mothers residing in the local government area during 2002 were included. Infants were identified and results interpreted in consultation with Indigenous health workers. Main outcome measure: Infant birthweight. Results: Indigenous infants had a lower mean birthweight than non-Indigenous infants (difference, 127 g), and were more likely to weigh <2500 g. Mothers of Indigenous infants were more likely to be single, aged <20 years and to smoke during pregnancy. Lower birthweight was associated with lower socioeconomic status for Indigenous and non-Indigenous infants. Indigenous infants in the most socioeconomically disadvantaged quintile in this study were at higher risk and had a mean birthweight 204 g less than non-Indigenous infants in the same quintile. In multivariate analysis, differences in birthweight were associated with socioeconomic status and smoking during pregnancy. Conclusions: For both Indigenous and non-Indigenous infants, birthweights were associated with socioeconomic status. Differences between Indigenous and non-Indigenous infants were largely explained by low socioeconomic status and smoking during pregnancy.