Recent theoretical models suggest that repetitive negative thinking might be a key mechanism explaining the negative effects of maternal psychopathology on mother-infant relations. While an emerging body of research largely supports this idea, the relative importance of differences in the trajectory of repetitive negative thinking during and after pregnancy for mother-infant bonding as well as maternal depressive symptoms is currently unknown. Therefore, we investigated associations between the course of maternal repetitive negative thinking during pregnancy and after birth and mother-infant-bonding and maternal depressive symptoms in a longitudinal study. The overall level of repetitive negative thinking was a significant predictor of mother-infant bonding, maternal anxiety and rejection in dealing with her infant four months after birth. Furthermore, differences in the trajectory of repetitive negative thinking predicted bonding, but not anxiety or rejection. The overall levels of repetitive negative thinking as well as the differences in the trajectory of repetitive negative thinking were significant predictors of maternal depressive symptoms. These findings indicate that changes of repetitive negative thinking during and after pregnancy can increase the risk of postpartum depressive symptoms.