Multiple risk is associated with adverse developmental outcomes across domains. However, as risk factors tend to cluster, it is important to investigate formation of risk constellations, and how they relate to child and parental outcomes. By means of latent class analysis patterns of prenatal risk factors were identified, and relations to interactional quality, parenting stress, and child internalizing and externalizing behaviors were investigated. An array of prenatal risk factors was assessed in 1036 Norwegian pregnant women participating in a prospective longitudinal community-based study, Little in Norway. Mother-infant interactions were videotaped and scored with the Early Relational Health Screen (ERHS) at 12 months. The Parenting Stress Index (PSI) and Infant-Toddler Social and Emotional Assessment (ITSEA) were administered at 18 months. First, we analyzed response patterns to prenatal risks to identify number and characteristics of latent classes. Second, we investigated whether latent class membership could predict mother-child interactional quality, parenting stress, and child internalizing and externalizing behavior after the child was born. Results revealed three prenatal risk constellations: broad risk (7.52%), mental health risk (21.62%) and low-risk (70.86%). Membership in the broad risk group predicted lower scores on interactional quality, while membership in the mental health risk group predicted less favorable scores on all outcome measures. Prenatal risks clustered together in specific risk constellations that differentially related to parent, child and interactional outcomes.