The purpose of the present prospective study is the analysis of risk and protective factors of perinatal stress and psychological distress of parents with or without a preterm child. Stress is measured biologically by Cortisol levels and psychologically by a questionnaire. Different outcomes of psychological distress (e.g. anxiety, depression, posttraumatic stress disorder, burnout) are measured by various questionnaires. We analyze the influence of different aspects as personality traits, social support, partnership.