Methods: This research was a descriptive-cross-sectional study conducted based on a causal-comparative design. The statistical population included all primiparous women in Kermanshah who referred to Motazedi Medical Center between February 2022 and April 2022. From the members of the community, 243 people were selected as a sample based on Cochran's formula. Sampling was done using the non-probability convenience method. The required data were collected using questionnaires, namely Edinburgh’s Postpartum Depression Inventory (2004), Orbach and Mikulincer Mental Pain Scale (2003), Sullivan, Bishop, and Pewick Pain Catastrophizing Scale (1995), and Harman's Childbirth Attitude Questionnaire (1998). Data were analyzed in SPSS28 using multivariate analysis of variance (MANOVA), at a significance level of 0.05.

Results: The results indicated that the mean scores of mental pain (M= 66.49, F= 60.65), pain catastrophizing (M= 46.85, F= 66.40), and fear of childbirth (M= 50.22, F= 65.01) were significantly higher in primiparous women with postpartum depression disorder than their counterparts without postpartum depression disorder (P< 0.05).

Conclusion: Based on the results of the present study and in line with the research literature, it can be stated that emotions such as fear, cognitive distortions (eg, catastrophizing and individuals' mentality in perceiving pain), and vulnerability are effective in depression after delivery.