Breast feeding provides short- and long-term health benefits for both infants and mothers. The World Health Organisation (WHO) and UK government recommend exclusive breastfeeding for the first six months of life but only 48% of infants in England are breastfed to any extent at 6–8 weeks ⁽¹⁾. There is concern that overuse of breast milk substitutes (BMSs) is driven by sophisticated marketing.

The aims of this study were to explore how mothers use labels on BMSs to inform their feeding choices and how they understand differences between formula products.

Semi-structured one-on-one interviews were conducted with mothers of children aged 0 to 3 years of age, who currently used formula to feed their infant and lived in Great Britain. Participants were recruited through social media. Socio-demographic data were collected via an online questionnaire and quota sampling was used to select participants according to socio-economic status (high, medium, low, based on a composite score^{Reference Kininmonth, Smith and Llewellyn2}) and age of child (<6 m, 7–11 m, 12–36m). The interview schedule included: 1. eliciting feeding experiences since birth, 2. a digital product mapping exercise to explore how participants made sense of the BMS market, 3. an exploration of salient BMS pack features. Interviews were audio-recorded, transcribed and analysed using NVivo 12. Thematic analysis was applied using an interpretivist approach. UCL Research Ethics Committee granted ethical approval for this study (Project ID:21253/001).

Online interviews were carried out in autumn 2021 with 25 mothers. Analysis generated three overarching themes: ‘brand’, ‘stages’ and ‘presentation’. Sub-themes within ‘brand’ included ‘trust’, as some women found it reassuring to use a brand they had grown familiar with through advertising and ‘they're all the same’ - while many believed there were no differences between brands, others felt certain products were superior or closer to breast milk. ‘Stages’ of formula were important to mothers, and sub-themes included ‘transition’ and ‘differences’, with many unsure whether there was a need to move from infant formula to follow-on formula. Among those who felt transitioning to follow-on formula was beneficial, there was uncertainty about how it differed from infant formula. Suggestions related to differences in energy content, micronutrients or consistency. ‘Presentation’ sub-themes included ‘premium products’, which were associated with scientific or medical expertise, and ‘key selling points’ which included organic classification and messaging relating to brands having expertise and research experience, which had health halo effects. Nutrition and health claims were rarely mentioned. Mothers’ milk feeding choices were informed by brand familiarity, the overall appearance of BMS packs and subtle health halo messaging, rather than explicit nutrition and health claims. Although mothers struggled to pinpoint nutritional differences between products, there was a belief that products varied according to brand and stage, and these perceived differences informed mothers milk feeding choices.