This supplement will contribute to the advancement of a program of research focused on the translation of health discoveries into clinical applications with the potential to increase pregnancy tobacco smoking cessation and prevent postnatal smoking relapse. This contribution will be significant because it focuses on high-risk couples and harnesses the broad functionality of smartphones to reduce smoking during pregnancy and postnatal relapse, with lifetime benefits for the family, while building mHealth research capacity. The supplement will increase the parent awards overall impact on the field of tobacco control during and around pregnancy.

This supplement will rely on a mixed-methods strategy to elicit patient-centred strategies from the ongoing trial participants and to pilot test selected strategies for increasing engagement and retention in the Smoke Free Together app. Specifically, we plan exit interviews with 15 pregnant smokers and 15 life partners (n=30) using the Smoke Free Together app in the parent project randomized controlled trial. These interviews will focus mostly on notification-based strategies. This supplement will also enrol 30 additional pregnant smokers and their life partners (additional n=60) and use mixed methods to test the efficacy of selected notification-based strategies on the engagement and retention in the Smoke Free Together app.