Informal Human Milk Sharing Practices: A Cross-Sectional Survey of Donors and Recipients in Ireland.

The provision of human milk is a global public health priority underpinned by its extensive benefits to infant and maternal health, and significant positive impacts within economic, societal, and environmental spheres. Informal human milk sharing (IHMS) is a contemporary and increasingly prevalent phenomenon which involves the exchange of human milk outside formal structures such as milk banks. This study aimed to investigate the characteristics, motivations, practices and experiences of donors and recipients who engage in IHMS in Ireland. A national cross-sectional survey included a validated questionnaire and was administered online in Ireland following ethical approval. The study is reported according to STROBE guidelines. Recipients reported significantly higher rates of cesarean sections, birth complications, and traumatic births compared to donors, with postpartum anxiety prevalent in both donors and recipients (51.4%). Recipients primarily sought donor milk due to perceived lactation insufficiency, concerns regarding commercial milk formula, infant related factors and belief in human milk benefits. Donors were motivated by altruism and the desire not to waste their expressed milk. Most donors (84.5%) considered formal milk bank donations but were inhibited by practical barriers, favoring informal sharing via online platforms and direct exchanges. There was minimal discussions with healthcare professionals about IHMS. The increasing significance of IHMS in Ireland is driven by diverse maternal and infant needs, and online communities. Future research should investigate safety outcomes and long-term impacts of IHMS, the lived experiences of donors and recipients, as well as the examination of strategies to enhance engagement with formal milk banks.