Evaluating early coparenting using the Lausanne Trilogue Play observational procedure: Guidance for infant–family practitioners from an international coparenting collaborative.

Since the early 1990s, coparenting - a conceptual framework connecting clinical insights from structural family therapy to theory and research on development of infants and toddlers within relationship systems - has brought new perspective to family and developmental science while hinting at ramifications for clinical practice. Coparenting theory and research evolved side-by-side with careful, intensive study of mother-father-child triangular relationships in families with very young children, work that expanded in recent years to include studies of other coparent-child triangular systems, such as those involving mothers, grandmothers, and infants. Until now, however, there has been no coordinated expert guidance for bringing concepts expounded in research studies of coparenting and triangular relationships to practitioners who work in infant-family mental health and family therapy contexts. In 2022, a Collaborative of family-oriented infant mental health experts from seven countries, all bringing proficiency in assessing and working with coparenting and triangular family dynamics in research or clinical settings, organized to review and identify common agreed-upon behavioral manifestations of coparenting during triangular interactions. Recognizing four central dimensions capturing how coparents and children organize when interacting together as a triangular system (engagement, teamwork, conflict, and child focus), the International Coparenting Collaborative (ICC) explains in this report how a standardized observational assessment, the Lausanne Trilogue Play (or LTP) can be used to identify coparenting strengths and challenges and elevate practitioners' attunement to coparenting dynamics within their therapeutic contexts.