It is commonly believed that pregnancy is a time of good mental health. However it has been observed, until recently, that many pregnant women, above all in post partum period, manifest depressive symptoms like sadness, social withdrawal and lack of motivation. The consequences are enormous, for mother mental health and for the psychical development of the baby. It becomes therefore necessary to screening and to precociously intervene on these pathological conditions and thanks also to the suitable knowledge of the risk factors for the potential development of depression post partum.