Risk factors for preterm, low birth weight and small for gestational age birth in urban Aboriginal and Torres Strait Islander women in Townsville

Objectives: To assess the characteristics of Indigenous births and to examine the risk factors for preterm (< 37 weeks), low birth weight (< 2,500 g) and small for gestational age (SGA) births in a remote urban setting. Design: Prospective cohort of singleton births to women attending Townsville Aboriginal and Islander Health Services (TAIHS) for shared antenatal care between 1 January 2000 and 31 December 2003. Main outcome measures: Demographic, obstetric, and antenatal care characteristics are described. Risk factors for preterm birth, low birth weight and SGA births are assessed. Results: The mean age of the mothers was 25.0 years (95% C 124.5-25.5), 15.8% reported hazardous or harmful alcohol use, 15.1 % domestic violence, 30% had an inter-pregnancy interval of less than 12 months and 9.2% an unwanted pregnancy. The prevalence of infection was 50.2%. Predictors of preterm birth were a previous preterm birth, low body mass index (BMI) and inadequate antenatal care, with the subgroup at greatest risk of preterm birth being women with a previous preterm birth and infection in the current pregnancy. Predictors of a low birth weight birth were a previous stillbirth, low BMI and an interaction of urine infection and non-Townsville residence; predictors of an SGA birth were tobacco use, pregnancy-induced hypertension and interaction of urine infection and harmful alcohol use. Conclusion: The prevalence of demographic and clinical risk factors is high in this group of urban Indigenous women. Strategies addressing potentially modifiable risk factors should be an important focus of antenatal care delivery to Indigenous women and may represent an opportunity to improve perinatal outcome in Indigenous communities in Australia.