In psychological, science and social research, infancy has been highlighted as a period of rapid cognitive, psychological and physical development in response to the environment the infant grows up in. In addition, these traditions of research have also emphasized how parental mental health problems can affect a parent’s ability to meet their infant’s needs. The approaches used in this practice area have not been analysed in the Swedish context considering their power implications to date. Following a qualitative research strategy, this thesis analysed descriptions of the approaches used in infant services work from the perspective of the workers. The four research questions focused on the descriptions of the circumstances around the families’ attendance to the service, ideal parent-infant relationships, the approaches used, the challenges encountered and the power implications for the parentinfant and worker-parent relationships. Semi-structured interviewing in English and Swedish was used to gather the data and thematic analysis to analyse it. The data was analysed using attachment theory, the motherhood constellation, the social approach to mental distress, the four modes of power and the concepts of care and control in social work. The data was coded into 7 themes that revealed a strong link between structural disadvantage and individual problems in relation to parental mental health problems, an eclectic approach to social work practice in infant services, focusing both on the internal representations of and on the behaviours in relationships. The study also revealed the strong effect of the care and control tensions on relationship building between workers and parents, intervention and on the emotional well-being of both parents and workers. The underlying themes of social control elements in infant services were interpreted as an example of the risk rhetoric in social work, while infant services practices also demonstrated elements of intuitive social work knowledge production evident in flexible role perception and the promotion of bonding and bridging in infant group sessions. The study advocates for a stronger emphasis on power relations analysis, on reflection about risk and for a more active dialogue between practice and research in social work with families facing parental mental health problems.