A behaviour change intervention to reduce home exposure to second hand smoke during pregnancy in India and Bangladesh:a theory and evidence-based approach to development

Background: Home exposure to secondhand smoke (SHS) is highly prevalent amongst pregnant women in low- and middle-income countries like India and Bangladesh. The literature on the efficacy of behaviour change interventions to reduce home exposure to SHS in pregnancy is scarce. Methods: We employed a theory and evidence-based approach to develop an intervention using pregnant women as agents of change for their husband’s smoking behaviours at home. A systematic review of SHS behaviour change interventions led us to focus on developing a multicomponent intervention and informed selection of behaviour change techniques (BCTs) for review in a modified Delphi survey. The modified Delphi survey provided expert consensus on the most effective BCTs in reducing home exposure to SHS. Finally, a qualitative interview study provided context and detailed understanding of knowledge, attitudes and practices around SHS. This insight informed the content and delivery of the proposed intervention components. Results: The final intervention consisted of four components: a report on saliva cotinine levels of the pregnant woman, a picture booklet containing information about SHS and its impact on health as well strategies to negotiate a smoke-free home, a letter from the future baby to their father encouraging him to provide a smoke-free home, and automated voice reminder and motivational messages delivered to husbands on their mobile phone. Intervention delivery was in a single face-to-face session with a research assistant who explained the cotinine report, discussed key strategies for ensuring a smoke-free environment at home and practised with pregnant women how they would share the booklet and letter with their husband and supportive family members. Conclusion: A theory and evidence-based approach informed the development of a multicomponent behaviour change intervention, described here. The acceptability and feasibility of the intervention which was subsequently tested in a pilot RCT in India and Bangladesh will be published later.