To examine dietary patterns changes from preconception to during pregnancy and their associations with socio-demographic and lifestyle factors.

This study used data from the Australian Longitudinal Study on Women’s Health (ALSWH), a population-based prospective cohort study. Women’s dietary patterns were assessed using Healthy Eating Index-2015 (HEI-2015) score and the four patterns were obtained from the factor analysis (Western diets, vegetable and grains, traditional vegetable and fruit patterns). Multi-variable linear regression and repeated measures mixed-effect models were used.

A national representative survey which covers all Australian citizens and permanent residents in Australia.

621 women were included from the ALSWH.

Women’s scores increased on the ‘HEI-2015’, ‘traditional vegetable’ and ‘fruit’ patterns while the ‘vegetable and grains’ decreased from preconception to during pregnancy. Women with higher education were more likely to increase their HEI-2015 score and fruit consumption from preconception to during pregnancy, respectively (β = 2·31, (95 % CI 0·02, 4·60)) and (β = 23·78, (95 % CI 4·58, 42·97)), than those with lower educational status. Single women were more likely to increase the consumption of vegetables and grains compared to married women (β = 76·08, (95 % CI 20·83, 131·32)). Women with higher income had a greater increase in the HEI-2015 score than those with lower income (β = 3·02, (95 % CI 0·21, 5·83)).

The findings indicate that there have been marked dietary changes from preconception to during pregnancy. Changes in healthy dietary patterns were influenced by education, marital status and income.