The objective of this study was to test whether 2 interventions promote interest in diabetes prevention among women with a history of gestational diabetes mellitus, who face high lifetime risk for diabetes. We designed an email outreach message promoting an existing preventive lifestyle program. The message incorporated values affirmation, a theory-based intervention that can improve openness to health information but typically relies on a writing exercise less practical in health care settings. In a 3-arm randomized study, 237 women with elevated body mass index and a history of gestational diabetes mellitus were randomized to read an outreach message containing either no affirmation (control) or 1 of 2 affirmations, streamlined to remove the typical writing exercise: either a values affirmation prompting reflection on any personal value, or a parenting affirmation prompting reflection on caregiving-related values. Outcomes included demonstrating interest in the lifestyle program (seeking information about it or intending to join) and seeking publicly-available health information about diabetes prevention. Compared with control, participants randomized to the values affirmation more frequently demonstrated interest in the lifestyle program (59.0% vs. 74.4%; adjusted relative risk: 1.31; 95% confidence interval: 1.04-1.66) and sought information about diabetes prevention (59.0% vs. 73.4%; adjusted relative risk: 1.22; 95% confidence interval: 0.97-1.54). The parenting affirmation yielded no significant differences in either outcome. A streamlined values affirmation, designed for feasibility in a health care setting, can promote interest in diabetes prevention among women at high risk. Research is needed to evaluate its effects on diabetes prevention program enrollment and clinical outcomes.