Background: Human milk is the optimal form of infant nutrition. If mother's own milk is unavailable, families may seek alternative sources of human milk through milk sharing, despite potential health and safety risks with this practice. Objective: The purpose of this scoping review was to synthesize the current literature on human milk sharing in the United States to help health care professionals better understand how families may use this practice for infant nutrition. Methods: A systematic search was conducted in June 2021 using Ovid MEDLINE, Embase, CINAHL, ProQuest Central, Web of Science, and Google Scholar. Articles were included if the primary outcome was milk sharing, excluding milk banks and preterm hospitalized infants. Results were limited to studies conducted in the United States and published in English after January 1, 2000. Results: From 2,124 articles, 34 met inclusion criteria and were reviewed. Study designs were largely observational (30/34), and participants were predominantly white, married, and middle-income women experiencing lactation problems or in possession of excess breast milk. Milk sharing, not for profit, was often facilitated through the internet but exchanged in person. Conversely, for-profit milk sharing often involved shipping and studies found evidence of milk contamination. No studies documented infant harm. Conclusions: There is limited research on the milk quality and relative risks of milk sharing, and no research on clinical outcomes in infants fed shared milk. Clinicians have opportunities to engage in open conversations about this practice to guide risk mitigation, however, research on recipient infant outcomes are urgently needed to inform best practices.
Keywords: breast milk; donor milk; human milk; human milk selling; informal milk sharing; peer-to-peer milk sharing.