The aim of the study was to assess the severity of depressive symptoms, to analyze risk factors for perinatal mental disorders and to assess dispositional optimism. A total of 106 women from Poland were included in the study at 37-week pregnant and 6 weeks after giving birth. It was demonstrated that the main predictors of perinatal mental disorders were the variables: mental health disorders before pregnancy, subjectively reported decreased mood in pregnancy, the lack of social (instrumental) support and the tendency to pessimism. The results of the study suggest how important it is to introduce clinical practice in Poland to screen for early detection of the risk of depression during pregnancy and postpartum depression.