We investigated whether informing first-time mothers about postpartum depression affects their experience and behaviour during the depression occurring in the first two weeks after birth.138 first-time mothers who were participants in a longitudinal study sponsored by the Swiss National Fund were retrospectively surveyed concerning postpartum depression in the week after birth (response rate: 86.9%).90% of the new mothers were affected. One fourth reported severe to very severe symptoms. The most popular sources of information about postpartum depression were books (65.8%) and magazines (59.2%). 10% of the mothers received information from their gynaecologist. 33% of the mothers with severe to very severe symptoms reported that after the birth no member of the medical or paramedical professions had discussed postpartum depression with them. Among the mothers who knew about postpartum depression, 30% did not feel adequately prepared for the degree of depression. Comparisons between informed and non-informed mothers show that the informed mothers had fewer symptoms, a shorter duration, and suffered less. In addition, the following reactions were noted: the informed mothers complained less and were less likely to believe that they were alone in their suffering. Also, they tended to have less negative thought patterns, felt less powerless, and were better able to explain their feelings and behaviour.Information about postpartum depression, especially to ensure that new mothers "feel prepared for it", has a positive influence on experience and behaviour in the week after birth. Therefore, it is useful to inform women about postpartum depression before the birth. This could be integrated into the neonatal care programme offered by the woman's gynaecologist. At the same time, training for nursing staff concerning postpartum depression is recommended.