Objective: To describe the prevalence and distribution of alcohol consumption during pregnancy in an Australian population over a 5-year period. Design, setting and participants: Cross-sectional repeated sample, trend analysis of aggregated and stratified alcohol consumption patterns during pregnancy. Pregnant women were enrolled from 2007 to 2011 in the Griffith Study of Population Health: Environments for Healthy Living, a birth cohort study being conducted in south-east Queensland and north-east New South Wales. Main outcome measures: Sociodemographic and alcohol consumption data were self-reported at enrolment. Alcohol measures included alcohol consumption (any level) and high-risk alcohol consumption, both during pregnancy (at any stage) and after the first trimester of pregnancy. Results: Of 2731 pregnant women for whom alcohol consumption data were available, a decrease in alcohol consumption was observed over the study period; 52.8% reported alcohol use in 2007 compared with 34.8% in 2011 (P < 0.001). The proportion of women who drank alcohol after the first trimester of pregnancy declined from 42.2% in 2007 to 25.8% in 2011. However, high-risk drinking patterns - at all or after the first trimester - did not change over the 5 years (P = 0.12). Low-level alcohol consumption was associated with older women (P < 0.001), more highly educated women (P = 0.01), and women from higher-income households (P < 0.001). In contrast, high-risk consumption after the first trimester was associated with lower levels of education (P = 0.011) and single-parent status (P = 0.001). Conclusions: This study showed a steady and statistically significant decline in the proportion of women who reported drinking alcohol during pregnancy from 2007 to 2011. To further reduce these levels, we need broad public health messages for the general population and localised strategies for high-risk subpopulations.