Postpartum depression (PPD) can occur through all the perinatal period and it is a public health problem. Positive and negative affect (at pregnancy and previous postpartum moments) are protective and risk factors for PPD. The Profile of Mood States (POMS) factor structure at pregnancy and three months postpartum has already been explored.

to explore the POMS factor structure at six and 12 months postpartum.

336 women (mean age=30,3; SD = 4,09; range=19-42 years) and 276 women (mean age=30,5; SD=3,99; range=19-41 years), respectively, filled in the Profile of Mood States (POMS), at six and 12 months postpartum.

A principal components analysis revealed, at six months postpartum, three components that explained 54,12% of the total variance: F1 Depression-Hostility (21 items; 39,5% explained variance/EV); F2 Anxiety-Anger/fatigue (14 items; 10,1% EV) and F3 Vigor-Activity (12 items; 4,8% EV); at 12 months postpartum, revealed also three components, that explained 46,16% of the variance: F1. Anxiety-anger/fatigue (13 items; explained 30,4% of the variance); F2. Depression-Hostility (6 items; 11,2% VE); F3. Vigor-Activity (14 items; 2,9% EV). At both postpartum moments, F1 and F2 can be summed to calculate Negative Affect (Cronbach Alpha, α=0,968 at six months and α=0,948 at 12 months). F3 corresponds to Positive Affect (α=0,863; α=0,875, respectively, at six months and 12 months).

The POMS factor structure at six and 12 months is robust, meaningful and can now be used to explore different aspects of the postpartum experience, at these postpartum moments.