The Psychiatry department of the University Hospital Centre of Lille has developed, over the last 10 years, a treatment network for psychiatric disorders during pregnancy or in the post-partum period. There are liaison consultations in the maternity department, screening and management of psychopathological disorders in the perinatal period, training of midwives, support of patients seeking genetic counselling, collaboration with teams providing "medically-assisted procreation", etc. For severe disorders of the post-partum period (severe depression, serious alteration of mother-child interaction, puerperal psychosis), the Psychiatry department has a specialized unit where 3 "mother-child" groups can be admitted. This unit is particularly effective if the patients and their family understand this healthcare system and stick to it to a certain extent. Even if improvements are always possible, cases in which situations occur as an emergency, are when dysfunctions are most frequently seen. On 7th December 1998, a Crisis Intervention Unit (CIU) was created with 15 short-term beds, for stays up to 72 hours. The CIU was opened in the Psychiatry department, close to the main Accident and Emergency department, with 2 aims: firstly to provide a setting and resources for a number of emergency psychiatric situations, and secondly to provide a place and time for crisis situations which we admit to the unit, with a view to facilitating interaction and to propose in certain cases a process of crisis intervention, which later continues on an outpatient basis. After being open for a year, the CIU has proved to be an improvement to all of the healthcare services which are available. It should be noted that the situations which need highly specialized resources in such a short time, are those which cause the most acute problems. This is at times when the emergency services network, with its internal logic, require another network based on a different logic, that the interface problems are at their most acute. The situations reported here, which require a fluid interface between the emergency services and the "mother-child" networks, are examples. We report 3 clinical situations, which illustrate 3 possibilities of action: the first, in which 2 successive stays in the CIU allowed an admission to the "mother-child" unit in satisfactory conditions, the second, in which overall management was based on hospitalization in the Obstetrics department and several visits to our Unit, and the last one, in which the whole medico-psycho-social approach was set up after a single stay of 3 days. Since the opening of Crisis Intervention Unit, around 1,000 patients have been treated there; 37 were women with difficulties with their pregnancy, 17 of whom required direct intervention by the "mother-child" team. The contexts were: 5 prenatal depressions, 4 post-partum depressions, 3 cases of hyperemesis gravidarum, 5 rejections of pregnancy and/or situations at risk of infanticide. The almost constant suicidal risk should be noted, or even attempted suicide, at the time of admission to the CIU. The other 20 women had psychopathological disorders linked to sterility, medically-assisted pregnancy, termination of pregnancy or pregnancy in women suffering from long-term somatic illnesses (insulin-dependent diabetes, lupus, etc.). When a psychopathological episode occurs during pregnancy, it is essential to preserve the developing relationship with the child in an intermediate place, in a healthcare perspective and to prevent any future impairment of the quality of the mother-child relationship by the psychiatric disorder. The Crisis Intervention Unit is not an emergency "mother-child" unit. Other French experiences have been reported, an example being mother-baby hospitalization in a crisis centre. The aim of our interventions is not the same, and our local context, together with the availability of a healthcare network on different floors, which is specific and close-by, allows this approach. Also, the contribution of Liaison Psychiatry in emergency situations should not be minimized. It is necessary to work in collaboration with the obstetricians. In fact, the chance to work with us was given by asking for a hospitalization in the Obstetric unit, during the prepartum period of pregnancies with a psychiatric risk. This way of proceeding allows somatic monitoring in hospital to be performed, whenever the risk run by the mother and/or the child requires it. This "analogue" procedure, however preventative it may be, does not always allow specific treatment of the psychiatric disorders to be given, despite liaison psychiatry interventions. Our interventions are not a specialized "mother-child" unit, or a substitute for Liaison Psychiatry, but they are specifically aimed at the context of the crisis. Obviously, it is precisely this dimension of the crisis which makes the other types of management temporarily unsuitable. This new working framework, with the simple possibility of admitting women and interacting with them in a crisis situation, with the aid of the competence of "mother-child" teams, most often seems to allow an alternative to hospitalization in the Psychiatry department, at the same time keeping up quality management of problems linked to the pregnancy or post-partum period. The specificity of the CIU, with its project of taking the special psychiatric vulnerability of pregnancy into account, makes sure that the psychopathological aspects of the crisis situation and the physiological aspects of adaptation reactions to the perinatal period are not neglected, but that are respected by this type of interaction/intervention.