To examine how household members, community health research workers (CHRWs) and broader social networks influenced pregnant women’s capabilities, opportunities and motivations to consume a daily balanced-energy protein (BEP) supplement or a multiple micronutrient supplement (MMS) in the context of an effectiveness trial in rural Bangladesh.

In-depth interviews, group interviews, focus group discussions, thematic analysis using the Capability, Opportunity, Motivation-Behaviour (COM-B) framework.

Gaibandha, Bangladesh.

Women (n=32) who had completed participation in the TARGET-BEP randomised trial, their husbands (n=13) and mothers-in-law (n=13), who participated in 13 group interviews, and CHRWs (n=39) who participated in six focus group discussions.

Capability to adhere to BEP and MMS was strengthened when family members understood the value of supplements and actively supported supplementation. Children emerged as unexpected facilitators, reminding mothers to consume supplements and tracking intake. Opportunity to use supplements consistently was enhanced by women’s educational attainment and the availability of household resources. Finally, motivation to take the supplements was influenced by many actors including neighbours, who could offer support but also often transmitted rumours and taboos, and CHRWs, who adeptly adapted adherence messages to the local context and to women’s specific concerns.

To improve antenatal supplement adherence and maternal–infant health in Bangladesh and similar contexts, pregnancy nutrition programmes should move beyond the woman-as-sole-agent paradigm by: (1) co-designing messages for husbands, mothers-in-law, children and neighbours in conversation with effective community health workers, such as those working in the TARGET-BEP trial; (2) equipping community health workers with flexible, family-engaging counselling strategies; and (3) complementing women’s education gains with gender-transformative and family-inclusive interventions.

ClinicalTrials.gov NCT05576207