Results: Determinants of change, post-test scores of knowledge, experiential and behavioural processes and self-efficacy were significantly different between the intervention group and comparison group among both pregnant women and mothers. Among pregnant women, the intervention group had significantly higher post-test scores than the comparison group. The distribution of percentages in three stages of change (Precontemplation, Contemplation/Preparation and Action/Maintenance) was significantly different between the two groups among both pregnant women and mothers. However, a higher percentage of mothers made progress in stages of change compared with pregnant women.