Facilitators and Barriers of Wet Nursing from Antiquity to the Present: A Narrative Review with Implications for Emergencies.

If maternal breastfeeding is not possible, wet nursing allows infants to receive the nutrition and protection against disease that breastfeeding provides. Such protection may be particularly valuable in emergencies. However, while wet nursing is recommended in the Operational Guidance on Infant and Young Child Feeding in Emergencies it is underutilized. This narrative review aimed to develop an understanding of wet nursing practice across time and location, and why wet nursing is currently so little supported to inform interventions to support wet nursing in emergencies. Medline and Embase were searched for "wet nursing," "cross-nursing," "shared breastfeeding," and "non-maternal nursing". Included articles were inductively analyzed to identify positive and negative factors associated with previous wet nursing practice. This review included 74 records. Our analysis of the wet nursing literature includes historical and contemporary themes with milk kinship and wet nursing as risky being shared themes across time periods. Our analysis revealed that it is how wet nursing is undertaken that influences whether it benefits women, children, and societies or not. Facilitators and barriers to wet nursing in emergencies related to infant mortality rates, cultural and individual support for wet nursing, availability of wet nurses, and resources to support wet nursing. Understanding the conditions under which wet nursing has positive outcomes and what can be done to facilitate beneficial wet nursing practices will assist in enabling wet nursing to be more commonly implemented in emergencies.