Objective: To examine overall micronutrient intake periconceptionally and throughout pregnancy in a population-based cohort of Australian women. Design: In a prospective cohort study, micronutrient dosages were extracted from self-reported maternal supplement use, recorded pre-conception, and for each trimester of pregnancy. A food frequency scale (DQESv2) captured usual maternal diet for gestational weeks 14-26. The influence of sociodemographic and lifestyle factors associated with supplement use was examined using logistic regression, and changes in micronutrient intakes prior to and throughout pregnancy were assessed using repeated-measures ANOVA analyses. Setting: Metropolitan hospital sites in Melbourne, Australia. Subjects: Women with a viable singleton pregnancy were recruited at less than 19 weeks' gestation (n 2146). Results: Compared with non-users, women using supplements during pregnancy were more likely to have planned their pregnancy, be >25 years old, primiparous, Caucasian, non-smokers, have a tertiary education and be consuming a folate-rich diet. Intakes of folate, Fe and Zn were significantly lower in the periconceptional period, compared with other periods (P < 0·001). Intakes below Recommended Daily Intake levels were common both periconceptionally and throughout pregnancy, with 19-46 % of women not meeting the Recommended Daily Intake for folate, 68-82 % for Fe and 17-36 % for Zn. Conversely, 15-19 % of women consumed beyond the recommended Upper Limit for folate and 11-24 % for Fe. Conclusions: The study highlights the need for improved public health education on nutritional needs during pregnancy, especially among women with lower educational achievements and income.