Although the obstetricians have been aware of puerperal psychiatric events, atypical postnatal depression was only identified during the 1960s. Early screening is therefore required to enable preventive measures to be taken. Our prospective study was intended to uncover early signs of, or a predisposition towards, postnatal depression before postpartum discharge from the hospital. Studying a population of 186 women who had just given birth and using two tools, the self-administered questionnaires designed by Pitt and by Cox, we found a relationship between postpartum blues, evaluated with Pitt's tool on the 3rd day after delivery, and postnatal depression, evaluated 8 months later. We thus show that the postpartum blues, evaluated with Pitt's tool, especially when severe, is predictive of the subsequent development of postnatal depression.