This article explores the accounts of six white, ‘middle-class’ women living in the UK who as first-time or recent mothers experienced thoughts of intentionally harming their newborn infants. Our analytic approach is psychosocial insofar as we take the women’s accounts as being conditional on a merging of social, discursive and psychological elements. Two dominant ways of relating to thoughts of harm are highlighted. The first is to do with the exclusion of such thoughts as indicative of unhealthy non-containment and depressive illness. The second involves including thoughts of harm as an extension of maternal vigilance and care. Here we draw on recent feminist understandings of a mother’s ambivalence as involving a heightened awareness of her own sense of self and her world through her relation to her child. It is argued that the disassociation of non acted-out destructive impulses from normative mothering perpetuates the usual pathologization of thoughts of harm and the associated vilification of women. Recent calls for the normalization of thoughts of harm that can be experienced by many new mothers are also challenged as leaving in place the idea that the experience of thoughts of harm is incongruous and debilitating to motherhood. In contrast, we make a case for thoughts of destructive harm as being a creative impulse that can be constructively incorporated into mothering and maternal subjectivity.