Background/Objectives: Valid and time-efficient measurement instruments for the assessment
of perinatal distress beyond depressive symptoms are yet to be determined. The main objective was to analyse the psychometric measurement properties of the Depression Anxiety Stress Scales (DASS) short forms in Swedish pregnant women during the third trimester. The secondary objective was to analyse the measurement properties of DASS short forms for the postnatal period. Methods: Data from the Scania Birth Cohort study including 78 women followed prospectively from the third pregnancy trimester to one year postpartum were used. The DASS-21, DASS-12, DASS-9 (two versions), and the 12-item Mini-DASS were analysed using confirmatory factor analysis (CFA), inter-item analysis, and Spearman’s rho subscale cross-correlations. Postnatal analysis at infant ages 1, 6, and 12 months was performed using CFA and inter-item analysis. Results: When used with third-trimester pregnant women, the DASS-9 version 1 and the Mini-DASS exhibited overall acceptable psychometric properties in terms of internal consistency (McDonald’s ω ≥ 0.77) and structural and discriminant validity (e.g., CFI > 0.90 and SRMR < 0.08 for all DASS-9 two- and three-factor models; and CFI > 0.95 and SRMR < 0.08 for one-factor models of the Mini-DASS subscales – including a modified anxiety scale – and for the Mini-DASS depression and anxiety two-factor model). Support for these DASS short forms postpartum was also indicated. Conclusions: Although preliminary, the current results support the DASS-9 and the ini-DASS as parsimonious tools for the assessment of perinatal distress and its subtypes. Further validation in the perinatal context is warranted.