Social media platforms have facilitated the use of shared breast milk for infant feeding since 2010. This study aims to assess the prevalence of shared milk use among breastfeeding mothers with insufficient milk supply; and compare shared milk users with non-users. Data were collected from breastfeeding mothers with low milk supply through an anonymous Internet-based survey in 2013. Shared milk users were those who used shared milk for at least 10% of their infant's needs; the rest were considered non-users. Chi-square comparisons between these groups assessed reasons and information sources for supplementation options; breastfeeding and supplement choice satisfaction; and breastfeeding duration. One hundred thirty-eight (29.1%) of 475 participants reported shared milk use. Healthfulness and reduced risk were most important to users (p < .001), whereas non-users cited convenience and lack of knowledge about other options (p < .001). Users reported receiving information from medical/breastfeeding professionals and online discussion forums, whereas non-users were more likely to not seek information about supplementation options. Users of shared milk were significantly more likely to provide breast milk at 6 months (59.3% vs. 39.6%, p = .001) and be satisfied with their supplementation choice (p < .001) compared with non-users. For women with self-reported lactation insufficiency, this study found that shared milk users were more likely to breastfeed longer, seek resources, identify healthful options, and report greater satisfaction with their supplementation choice than non-users. Importantly, shared milk may play a role in achieving U.S. Healthy People 2020 targets for breastfeeding duration.
