Supplementary Information for the Manuscript (Determinants of prenatal breastfeeding knowledge, attitudes, and self-efficacy among Burmese migrant pregnant mothers in Samut Sakhon Province, Thailand: a cross-sectional study)

<b>Objective: The study aimed to </b>explore the determinants of prenatal breastfeeding knowledge, attitudes, and self-efficacy among Burmese migrant pregnant mothers in Samut Sakhon Province, Thailand.<b>Design: </b>The data were collected as part of a baseline survey of a randomized controlled trial.<b>Setting and participants:</b> A total of 198 Burmese migrant mothers between 28^th and 34^th weeks of gestation were recruited from the antenatal care clinic of Samut Sakhon Hospital.<b>Primary outcome measures:</b> Breastfeeding knowledge, attitudes, and self-efficacy<b>Results: </b>The prevalence of good breastfeeding knowledge was 65.7%, positive attitudes towards breastfeeding was 55.1%, and high breastfeeding self-efficacy was 70.7%. Multivariate logistic regression models revealed that mothers aged above 25 years (AOR=3.10, 95%CI: 1.21–7.94), being Bamar (AOR=2.33, 95%CI: 1.22–4.44), having support from husband (AOR=2.34, 95%CI: 1.20–4.58), and having previous childbirth experience (AOR=2.46, 95%CI: 1.26–4.81) were the main determinants of good breastfeeding knowledge. Similarly, being Bamar (AOR=2.82, 95%CI: 1.51–5.25), having high school education (AOR=4.27, 95%CI: 1.80–10.09), and having access to workplace breastfeeding support (AOR=5.32, 95%CI: 1.41–20.07) were found to be significant predictors of positive attitudes towards breastfeeding. Moreover, mothers aged above 25 years (AOR=2.89, 95%CI: 1.07–7.84), being Bamar (AOR=2.42, 95%CI: 1.15-5.09), being unemployed (AOR=7.75, 95%CI: 1.89–31.86), having support of husband (AOR=3.20, 95%CI: 1.46–7.03), having previous breastfeeding experience for six months or more (AOR=4.97, 95%CI: 2.12–11.65), and having intention to exclusively breastfeed (AOR=2.70, 95%CI: 1.25–5.83) had significant associations with high breastfeeding self-efficacy.<b>Conclusion: </b>The prenatal breastfeeding knowledge, attitudes and self-efficacy among Burmese migrant mothers were influenced by many factors. A comprehensive understanding of these factors will enable policymakers and healthcare providers to develop context-specific interventions for the promotion of exclusive breastfeeding among Burmese migrant mothers in Thailand.