The perinatal period is increasingly recognized as a vulnerable time for the development and exacerbation of psychopathology symptoms. Research has often focused on perinatal depression, with limited information on perinatal anxiety. This study examined the psychometric structure of all anxiety and depressive disorder symptoms as well as explored the relation between perinatal internalizing symptoms and sociodemographic, obstetric, and psychological risk factors. Obsessive-Compulsive Disorder (OCD) is a common perinatal anxiety disorder that is now classified with the Obsessive-Compulsive Spectrum (OCS) (hoarding, body dysmorphic, trichotillomania, and excoriation disorders). This study also aimed to determine the prevalence of clinically significant OCS symptoms and their association with postpartum adjustment. Participants recruited from the University of Iowa Hospitals and Clinics (N =246) completed an online questionnaire and a structured clinical interview during pregnancy (28-32 weeks gestation) and the postpartum (6-8 weeks). Questionnaires assessed demographics, pregnancy complications, anxiety sensitivity, coping strategies, maternal attitudes and experiential avoidance. Clinical interviews dimensionally assessed all anxiety and depressive symptoms as well as past psychiatric diagnoses. Confirmatory factor analyses identified three factors: Distress (depression, GAD, irritability, and panic); Fear (social anxiety, agoraphobia, specfic phobia, and OCD); and Bipolar (mania and OCD) during pregnancy and the postpartum. During pregnancy, structural equation modeling demonstrated that past psychiatric history predicted Distress and Fear symptoms. Experiential avoidance mediated the relation between negative coping strategies and Fear symptoms. In the postpartum, negative maternal attitudes predicted Distress symptoms. Experiential avoidance mediated the relation between negative coping strategies and Fear symptoms as well as between anxiety sensitivity and Fear symptoms. There were low rates of clinically significant OCS symptoms, except for body dysmorphic disorder symptoms. Elevations in all OCS disorder symptoms were significantly associated with more difficulty adjusting to the postpartum. Past psychiatric history, negative maternal attitudes, and experiential avoidance are particularly important risk factors for perinatal anxiety. Future clinical research should be aimed at identifying at-risk women and modifying experiential avoidance during the perinatal period. Elevated OCS symptoms, particularly body dysmorphic disorder symptoms, affect postpartum adjustment. Future intervention work should focus on assessing and treating perinatal body dysmorphic disorder symptoms.