BACKGROUND-AIM:
Pregnant women are primarily exposed to secondhand smoke (SHS) in private environments such as the home, mainly due to their male partner’s smoking. Previous interventions have typically targeted pregnant women, providing them information and tools, despite many women feeling uncomfortable confronting their partners to smoke only outdoors. This study aimed to assess the feasibility and preliminary effectiveness of First Breath—a digital behavioral intervention to support expectant fathers to reduce SHS exposure during pregnancy.

METHODS:
A pilot randomized controlled trial (RCT). Eligible participants were male, Hebrew-speaking, aged ≥18, smoking at least one combustible cigarette per day, and living with a pregnant partner (<25 weeks gestation). Exclusion criteria included engagement in a smoking cessation program, high-risk pregnancy, having a pregnant partner who currently smokes, or lack of internet access. Participants were randomized to receive either the First Breath intervention or general information about SHS (control). At baseline and 12-weeks follow-up, participants completed questionnaires including self-report of smoking rules at home and perceived SHS exposure (0–10 scale) of their pregnant partner.

RESULTS:
Of the 120 individuals screened, 45 (37.5%) met the eligibility criteria and provided informed consent. A total of 42 participants (93%) completed the follow-up assessment. Mean engagement time with the First Breath app was 13 minutes (SD = 0.6–42.8) in the intervention group (n = 22), compared with 1 minute (SD = 0.6–4) in the control group (n = 20). The SHS exposure score decreased from 5.5 at baseline to 4.3 after 12 weeks in the intervention group (p = 0.18) but slightly increased in the control group (4.6 to 5.4, p = 0.14). A significant reduction in smoking behavior (average number of cigarettes smoked per day) was observed in the intervention group (p=0.01), whereas no significant change occurred in the control group (p=0.1). In the intervention group, 4 participants (19%) reported a positive change in smoke-free home (SFH) rules, while 17 (81%) reported no change. In the control group, 3 participants (15.8%) reported a positive change, and 16 (84.2%) reported no change or a negative change in SFH rules.

CONCLUSIONS:
The First Breath intervention was feasible for expectant fathers and showed some preliminary effectiveness. Larger trials are needed to assess its impact on home smoking behaviors and prenatal SHS exposure. Findings will inform the design of a future full-scale RCT.