Importance. Peripartum depression (PeriPD) is a prevalent condition with serious, long-term consequences for mother and child. Emotion regulation (ER) is increasingly recognized as key factor for maternal mental health and parenting. However, evidence remains limited regarding the relation of ER difficulties and depressive symptoms across the peripartum. Objective. To determine whether self-reported ER difficulties in the antepartum are associated with depressive symptoms at multiple peripartum timepoints. Secondary: Whether PeriPD trajectories differ on antepartum ER difficulties. Design, Setting and Participants. Data for this study were collected from January 2022 to April 2024 through the Mom2B cohort, a population-based, prospective Swedish national study using a smartphone app for data collection. The cohort includes Swedish-speaking, pregnant women over 18 years, residing in Sweden, who downloaded the Mom2B app. Eligibility for this sub-study required verification of pregnancy and delivery, along with complete background information (N = 1414). Participants were included if they completed the Difficulties in Emotion Regulation Scale-16 (DERS-16) during the second trimester (N = 623). Exposure. DERS-16 total score at 16-25 weeks antepartum. Outcomes and Measures. Depressive symptoms were assessed using the Edinburgh Postnatal Depression Scale (EPDS) at seven timepoints: 24-34, 36-42 weeks antepartum, and 1-4, 6-13, 14-23, 24-35, 36-42 weeks postpartum. Multiple linear regression models examined DERS-16 scores as exposure, with EPDS scores as outcomes, adjusting for potential confounders. Secondary: Comparison of DERS-16 scores between PeriPD trajectories using ANOVA. Results. 623 pregnant women, aged 19-44, were included. DERS-16 scores were strongly associated with EPDS scores up to 14-23 weeks postpartum, even after adjusting for potential confounders (all regression coefficients = .06 - .23, all 95% CIs = .00 - .26, all p-values < .05). Secondary: 134 participants were classified into a specific PeriPD trajectory. DERS-16 scores differed between trajectories (F(4,129) = 26.68, p < .001, np2 = .45), with higher ER difficulties in early and late postpartum-onset trajectories compared to the healthy group (p = .017 and p = .018, respectively). Conclusion and Relevance. ER difficulties in the second trimester present a robust vulnerability marker for PeriPD symptoms, particularly for progression to postpartum depression. The DERS-16 may aid in early detection of peripartum mental health risks, while enhancing ER offers a promising intervention approach. Further research is needed to evaluate DERS-16's clinical utility and optimize ER-centered interventions for at-risk trajectories.
