The perinatal period (shortly before and after birth) is a particularly significant stage, providing a sound base for healthy development. Primary health care should accompany the individual through the entire life cycle, and mental health problems constitute a public health threat that calls for the development of mental health promotion initiatives in primary health care. Responding, in 2004 our team initiated an action research project with the aim of reorganising primary health care during pregnancy and the first year of life. The aim is to enable health professionals to support families in the transition to parenthood, thereby promoting children's mental health. In order to plan this reorganisation, we developed a two-step decision-making process: 1. assessment of antenatal health care; 2. joint reflection concerning the priorities for change. The study goal was to assess the particular characteristics and needs of families during the perinatal period as well as the kind of care they were actually receiving. We designed a cross-sectional quantitative-qualitative study that collected data from users and health professionals using questionnaires and semi-structured interviews. The reflection step took place during a workshop that aimed to analyse the results and discuss priorities. The study confirmed the need to search for mental health problems during pregnancy, particularly to prevent a disturbed mother/child bonding process, and the importance of emphasising issues such as communication, information provision and the adequate availability of health professionals for antenatal care. The findings led to the following conclusions: 1. risk and needs assessment regarding mental health and options for family support should be included in the protocols of antenatal care; 2. primary health care professionals should be enabled to undertake diagnostic work and problem solving related to mental health; 3. collaboration between different levels of health care and between health sector and community resources should be increased.The highly participative decision-making process used led to a selection of priorities and strategies that was meaningful to users and health professionals and should contribute to the implementation and sustainability of changes for mental health promotion.