Latent trajectory classes of postpartum depressive symptoms: A regional population-based longitudinal study.

Purpose: This study aimed to (a) assess trajectories of women's depressive symptoms during the first year postpartum to (b) identify potential unobserved classes of women as defined by their trajectories, (c) identify antepartum and early postpartum risk factors associated with trajectory classes, and (d) examine the association between trajectory classes and counselling during the postpartum period.

Methods: Data on depressive symptoms, using the Edinburgh Postnatal Depression Scale (EPDS), were collected from 1374 women across nine Norwegian well-baby clinics at 1.5, 4, 6, and 12 months postpartum. Well-baby clinics offer universal, free services to all families living in the municipality. Thus, there were no specific exclusion criteria for this study. All clinics had implemented the Edinburgh-method which combines screening for PPD, using the EPDS, with supportive counselling.

Results: Analyses showed that depressive symptoms decreased initially, followed by a flattening in symptoms at 6 months. Mixture analyses, however, identified two classes of women with distinct trajectories; (1) a low-risk (n = 1249, 91%) and (2) a high-risk group (n = 119, 9%). Complications after birth, elevated prenatal depressive symptoms, previous or current mental illness, and gestational week, predicted trajectory class membership. Women in the high-risk group were more likely to receive counselling than low-risk women.

Limitations: Women had higher educational level than the general population and one of the municipalities did not have a 12-months routine consultation.

Conclusion: Findings suggest heterogeneity among women in their depressive symptoms during the first year postpartum with a distinct set of risk factors associated with high-risk women. This has implications for the prevention and follow-up of women during pregnancy and the first year after childbirth.