For parents, the premature birth of a child represents a traumatic event for which they are poorly prepared. To date, the focus of scientific interest has been on maternal psychological stress responses, such as anxiety and depression, or on appropriate coping mechanisms, whereas only scant attention has been paid to the traumatic aspect of the maternal experience after very low-birth-weight (VLBW) birth. The present study is the first to investigate the posttraumatic stress response of mothers after the birth of a VLBW infant in a prospective longitudinal study.