RESUMO
BACKGROUND: Breastfeeding provides beneficial health outcomes for infants and their mothers, and increasing its practice is a national priority in many countries. Despite increasing support to exclusively breastfeed, the prevalence at 6 months remains low. Breastfeeding behavior is influenced by a myriad of determinants, including breastfeeding attitudes, knowledge, and social support. Effective measurement of these determinants is critical to provide optimal support for women throughout the breastfeeding period. However, there are a multitude of available instruments measuring these constructs, which makes identification of an appropriate instrument challenging. Research aim: Our aim was to identify and critically examine the existing instruments measuring breastfeeding attitudes, knowledge, and social support. METHODS: A total of 16 instruments was identified. Each instrument's purpose, theoretical underpinnings, and validity were analyzed. RESULTS: An overview, validation and adaptation for use in other settings was assessed for each instrument. Depth of reporting and validation testing differed greatly between instruments. CONCLUSION: Content, construct, and predictive validity were present for most but not all scales. When selecting and adapting instruments, attention should be paid to domains within the scale, number of items, and adaptation.