This equity audit assessed enrolment and completion of a state-funded cardiometabolic risk-reduction programme for women with prior gestational diabetes in Victoria, Australia. The analyses compared completion rates between the standard prevention programme <i>Life!</i> with one specifically adapted for women with prior gestational diabetes (<i>Life!</i> GDM) using the PROGRESS equity framework. Women with a history of GDM in the <i>Life!</i> GDM or the mainstream <i>Life!</i> programme in 2022-2025 were included. Multinomial logistic regression was used to impute categorical variables, logistic regression for binary variables, and linear regression for continuous variables. Estimates were combined across imputed datasets using Rubin's rules. A total of 2261 women were included: 370 in <i>Life!</i> GDM, and 1891 in <i>Life!</i> from 2022 to 2025, with completion rates of 36.7% and 52.2%, respectively. Compared with women in <i>Life!</i>, women in <i>Life!</i> GDM were more likely to come from non-English-speaking backgrounds, particularly South and Central Asian (30.5% vs. 17.0%) and South-East Asian backgrounds (13.0% vs. 4.3%). After multiple imputation, multivariable logistic regression showed that none of the examined participant characteristics were significantly associated with programme completion in <i>Life!</i> GDM. In the <i>Life!</i> cohort, completion was significantly associated with marital status, with single participants having lower odds of completion (OR = 0.59, 95% CI: 0.41-0.85), and with referral channel, with self-referral associated with higher odds of completion (OR = 1.71, 95% CI: 1.39-2.12). The adapted programme appeared to have reached more culturally and linguistically diverse women; however, lower completion among those experiencing disadvantage highlights the need for enhanced support and retention strategies to ensure equitable postpartum diabetes prevention.