Evaluating a hierarchical structural model of psychopathology symptoms across pregnancy and the postpartum period.

Pregnancy and postpartum are times of increased risk for a variety of mental health problems. Historically, these symptoms have been conceptualized via ostensibly distinct, consensus-based diagnostic categories. However, applying an empirically based, dimensional approach to psychiatric classification may significantly advance understanding of common and specific risk factors during this highly dynamic period. In the present study, we used exploratory psychometric methods to examine the structure of psychopathology symptoms from the "bottom-up" or using symptom-level co-occurrence to derive common factors in a sample of individuals (N = 347) across earlier pregnancy (M = 17.4 weeks gestation), later pregnancy (M = 34.6 weeks gestation), and postpartum (M = 25.3 weeks postpartum). We examined changes (or invariance) in symptom structure longitudinally. Results demonstrated a hierarchical structure of symptoms including a robust broad distress factor at the highest level, followed by replicable internalizing and externalizing factors. The best lower-order solutions included eight to nine factors at each timepoint. Across earlier to later pregnancy and postpartum, psychopathology structure showed both significant invariance and nuanced changes, indicating that perinatal symptom factors are largely robust, while the structure of select subfactors (e.g., low mood, general anxiety) differs slightly across time. Consistent pregnancy anxiety, traumatic stress, somatic problems, detachment, anger-antagonism, and inattention-hyperactivity factors emerged across timepoints. Factors relating to positive affect, low mood, general anxiety, and social anxiety were structured similarly although not identically across time. These longitudinal trends in psychopathology structure have important implications for empirically based psychopathology classification in this critical developmental phase. (PsycInfo Database Record (c) 2025 APA, all rights reserved).