Table 1 Multicomponent behaviour change intervention informed by the systematic review, modified Delphi survey and qualitative interviews

Decision to develop a multicomponent behaviour change intervention and 14 BCTs taken forward for inclusion in the modified Delphi survey

Measure cotinine (marker for SHS exposure) in non-smokers and give feedback

Pregnant women, husbands and family members have poor understanding of the health risks of SHS to the health of the pregnant women and their future child.

Pregnant women and family members think educating their husbands about the risks of his smoking to his future child may change his behaviour. Husbands agree this would motivate them.

The source of this education is seen as important with university employees or health professionals seen as more credible (and influential) than the pregnant woman.

Personalized feedback on the impact of SHS on the pregnant woman (and therefore her future child) is presented in an ‘official report’ (cotinine report).

Information about health consequences of SHS and of smoking restrictions at home

Story provides information on the health consequences of SHS to the entire family and the benefits of smoking restrictions in the home (picture booklet).

Feedback on the impact of the husband’s smoking in the home on his future child is directly targeted at the husband (letter from the future child).

Information about social and environmental consequences

Pregnant women lose confidence in asking their husbands to smoke outside. Some are frightened of his reaction.

The story shows the husband being receptive to discuss this with his wife (picture booklet).

Husbands are encouraged to discuss with their wives the steps they could take to make their home smoke free (voice messages).

Salience of consequences

Husbands do not acknowledge the impact of their smoking inside.

Emotive language directed at the husband is used (letter from the future child) and the story included pictures showing the impact on his entire family (picture booklet).

Identify reasons/motives for wanting and not wanting to stop smoking inside homes

Pregnant women dislike the smell of smoke, feel nauseous and struggle to breathe. They want a smoke-free home for their own and children’s health (also a motive for some husbands). Most husbands enjoy smoking in their home surrounded by family. They do not want to be seen smoking outside, dislike the cold and insects and fear fines/for their safety.

Clear consensus amongst pregnant women, husbands and family members that the husband’s priority is his children including the future child.

Story shows the pregnant woman and her husband sitting together to discuss the husband’s smoking and reasons why he should stop smoking in the home. Reference is made to the harms to children and future child from their father’s smoking indoors. Positive images of a smoke-free home, highlighting multiple benefits are depicted (picture booklet).

Feedback about the impact of the husband’s smoking in the home on his future child is directly targeted at the husband (letter from the future child).

Facilitate barrier identification and problem solving

Pregnant women repeatedly ask their husbands to smoke away from them and their children, or to smoke outside, with little success. They feel frustrated and often decide to give up. Husbands agree they usually ignore these requests.

Story shows the pregnant woman and her husband sitting down together to discuss the barriers to him smoking outside. There is an action plan for them to complete together (picture booklet).

Husbands are reminded to take steps to make their home smoke free (voice messages).

Prompt practice

Pregnant women report feeling unsupported by family members in challenging husbands’ smoking behaviours. They lose confidence to negotiate with their husbands and some are frightened of his reaction. Conversely, most husbands do not believe it is hard for their wives to request them to smoke outside.

Pregnant women think that if other family members, especially elders, ask the husbands to smoke outside, this may be successful. Requests from their children were also seen as potentially influential.

Story shows the pregnant woman asking for support from her family members to ask her husband to smoke outside. Women are instructed to enlist support from their own family members to negotiate with their husband (picture booklet).