IntroductionThe Depressive Anxiety and Stress Scale (DASS-21; Antony et al., 1998) had been widely used to measure psychological distress among clinical and non-clinical populations, including in Portugal (Pais-Ribeiro et al., 2004). Although DASS-21 has been considered useful to evaluate psychological distress in the perinatal period, studies reporting on its psychometrics are scarce (Brunton et al., 2015).ObjectiveTo investigate the psychometric properties of the DASS-21 in a Portuguese sample of pregnant women.MethodsFour hundred and twenty-seven pregnant women (mean age: 32.56 ± 4.785 years) in their second trimester of pregnancy (17.34 ± 4.790 weeks of gestation) completed the Portuguese versions of DASS-21 and of Postpartum Depression Screening Scale (PDSS-24; Pereira et al., 2013).ResultsThe DASS-21 Cronbach's alpha was “very good” (a = 0.92). Following the Kaiser and the Cattel Scree Plot criteria, two factorial structures were explored. Three factors structure (explained variance/EV = 57.18%): F1-stress (included 8 items; α = 0.89); F2-Anxiety (7 items; α = 0.79); F3-Depression (6 items; α = 0.82). In the two factors structure (EV = 50.96), the Stress and Anxiety items load in the same factor (F1: 15 items; α = 0.91) and the F2 is composed of the Depression items (F2: 6 items; α = 0.82). Pearson correlations between DASS-21 total and dimensional scores and the PDSS-24 scores were all significant, positive and moderate to high (@.50).ConclusionsThe Portuguese version of DASS-21 has good reliability, construct and concurrent validity when used with pregnant women. Its factorial structure significantly overlaps with the original, with only one item loading in another factor. DASS-21 could be very useful in diverse settings in the perinatal period.Disclosure of interestThe authors have not supplied their declaration of competing interest.