Interactive Theory of Breastfeeding: creation and application of a middle-range theory.

OBJECTIVE: To describe a breastfeeding theory based on King's Conceptual System.

METHOD: Theoretical study that used analysis of concept, assertion synthesis, and derivation of theory for the creation of a new theory.

RESULTS: King's system components were associated with elements of the breastfeeding process and a middle-range theory was created, which describes, explains, predicts, and prescribes breastfeeding by analyzing factors that precede and affect it, as well as their consequences on the breastfeeding process.

CONCLUSION: The Breastfeeding Interactive Model is abstract enough to be applied in different social, cultural, political, and economic contexts, because it conceptualizes breastfeeding in systemic, dynamic, and procedural aspects. Based on a conceptual model of nursing, it contributes to the scientific construction of the subject; however it can also potentially be applied by other professionals involved in breastfeeding assistance.