The birth of a preterm infant is often experienced as a highly traumatic situation. Many studies show that parents of preterm infants display post-traumatic stress and depressive disorders. We rely on ongoing research (PERAMQUAL project), to address the impact that such trauma have on the representation of the child by the parent and the construction of the relationship with this child. The following observations are taken from a corpus of 18 research interviews with fathers. Interviews were conducted during the hospitalization of the preterm infant. We observed that the representation of the child underwent biologisation, which means that it is represented as a foetus or an unfinished being. The difficulty to imagine this ‘unfinished being’ as a child seems to be related to the adoption of a defensive strategy against the risk of death. Child representation evolves through the development of the preterm infant, creative parenting relationships, and the help of caregivers who accompany parents. These results are an application of theoretical work on trauma and its impact on the individual.