Development of a complex intervention to strengthen municipality-based breastfeeding support to reduced social inequity in breastfeeding.

Background: Breastfeeding is the ideal nutrition for infants and protects infants and mothers from a range of adverse health outcomes during their lifespan. In Denmark, while the breastfeeding initiation rate is high, only 14% of mothers meet the World Health Organization's recommendation of exclusive breastfeeding at six months. Furthermore, a notable social inequity exists among those who achieve this recommendation. Knowledge of effective interventions to reduce breastfeeding inequity is limited. A previous hospital-based intervention succeeded in increasing breastfeeding duration. However, most breastfeeding support is provided in Danish municipalities by health visitors. This called for adapting the intervention to the health visiting program and developing an intensified intervention addressing the social inequity in breastfeeding. This article describes the adaptation and development process of a municipality-based intervention.

Methods: During a 15-month period in 2020-21, the municipal intervention was iteratively developed using a three-stage framework for developing complex health interventions described by Hawkins et al. The three stages were 1) need assessment and stakeholder consultation, 2) co-production and 3) prototyping. The process was inspired by O'Cathain et al.'s principles for a user-centred, co-created and theory- and evidence-based approach, involving parents and health visitors.

Results: In stage 1, we identified the needs and priorities of the target groups of the intervention. In stage 2, the intervention was developed through action research design and inspired by Duus' 'learning cycles' as the method to enhance motivation and ownership and to strengthen the implementation process by creating a joint room for learning and reflection with health visitors and developers. In stage 3, the intervention was tested for feasibility and usefulness during a 2.5-month period accompanied by monthly dialogue meetings with health visitors and developers. In this period, the intervention was refined based on the gathered experiences and was subsequently prepared for evaluation.

Conclusion: The description of the development of this complex intervention, aimed at increasing breastfeeding duration and reducing inequity, offers breastfeeding practitioners and researchers a transparent foundation for continuously improving breastfeeding support and a methodology for complex intervention development.

Trial Registration: Registered at Clinical Trials NCT05311631.