INTRODUCTION AND AIMS: There is limited research regarding the effects of alcohol consumption by breastfeeding mothers on infant development. This study examined the frequency, correlates and outcomes of alcohol use during lactation. DESIGN AND METHODS: Data were from an Australian cohort study. Maternal demographics and substance use were assessed during pregnancy and at 8 weeks and 12 months postpartum. Breastfeeding duration, infant feeding, sleeping and development (Ages and Stages Questionnaire) were also assessed postpartum. Logistic regression and general linear model analyses examined characteristics of women who drank during breastfeeding, and the association between alcohol use during breastfeeding and infant outcomes. RESULTS: Alcohol use was reported by 60.7% and 69.6% of breastfeeding women at 8 weeks and 12 months postpartum, respectively. Breastfeeding women who consumed alcohol were more likely to be born in Australia or another English-speaking country, be tertiary educated and have higher household incomes. Most drank at low levels (
