Child psychological / behavioral disorders such as withdrawal may persist when the psychosocial context is unfavorable. Health promotion strategies (Olds' paradigm) have proved their efficacy in vulnerable populations. CAPEDP project sets out to evaluate a program of home visits in France. 440 primagravida will be randomized into two groups. They will ALL be under 26 and vulnerable by having a low level of education AND/OR a low income AND/OR being socially isolated. The first group will receive routine follow-up as currently provided by national community health and social services. The second group will receive home visits by community workers. These visits will start during pregnancy and will continue up to the child's 2nd birthday. This program aims at reducing psychosocial disorders and promoting mental health, social support and attachment amongst at-risk young women and their families. The ten objectives for the home visiting : Enhancing parental skills, Preventing prenatal and postnatal depression, Preventing psychosocial disorders in the children, Promoting secure attachment in the children, Enhancing knowledge and use of available health, educative and social resources, Promoting parental self-esteem for their roles, Reducing parental stress, Enhancing mothers' social network and perceived support, Promoting psychomotor development in the children, Enhancing mothers' knowledge about child development. This will be the first time in France that such a program will be implemented. Our hypothesis is that a targeted prevention and health promotion will reduce physical and mental health care needs.This is also the first prospective randomized control trial in France on mother-child attachment.