B. longum ATCC BAA-999, or a composition comprising B. longum ATCC BAA-999, for use in an individual to support breastfeeding initiation and/or to optimise breastfeeding duration and/or to optimize the quality and/or quantity ofbreast milk and/or to prevent or treat peripartum emotional distress and/or to regulate amygdala activity and/or to regulate the release of CRH, and to prevent or treat the negative effects of peripartum emotional distress in the offspring of individuals.