BackgroundThe impact of Traditional Chinese Medicine (TCM) constitution on predicting perinatal depressive symptoms remains underexplored, particularly regarding its longitudinal association with postpartum outcomes and the mediating effect of antenatal depressive symptoms.ObjectiveThis study sought to examine the association between Traditional Chinese Medicine (TCM) constitution types during pregnancy and the risk of perinatal depressive symptoms, as well as to identify related influencing factors.MethodsA prospective cohort study was conducted, involving pregnant women at 10–14 weeks of gestation (n=1286). The Classification and Determination of Constitution in Traditional Chinese Medicine self-assessment form was employed to evaluate constitution types, while the Edinburgh Postnatal Depression Scale (EPDS) was utilized to assess depressive status during both pregnancy and the postpartum period. Additionally, pertinent demographic and obstetric characteristic data were collected. Mediation analysis with bootstrap resampling (5,000 iterations) was performed to examine indirect pathways.ResultsThe findings revealed that the qi-stagnation constitution was significantly associated with an increased risk of prenatal depressive symptoms (OR = 2.58, 95% CI: 1.59-4.19, P<0.001), whereas the balanced constitution was linked to a decreased risk of prenatal depressive symptoms (OR = 0.35, 95% CI: 0.24-0.51, P<0.001).After adjusting for antenatal depressive symptoms, the qi-stagnation constitution (OR = 2.04, 95% CI: 1.14–3.67, P = 0.017) and preterm birth before 34 weeks of gestation (OR = 4.26, 95% CI: 1.45–12.47, P = 0.008)have been identified as independent risk factors for postpartum depressive symptoms. Conversely, the balanced constitution demonstrates a protective effect(OR = 0.42, 95% CI: 0.26–0.68, P < 0.001). Additionally, prenatal depressive symptoms significantly elevates the risk of postpartum depressive symptoms (OR = 2.05, 95% CI: 1.35–3.09, P < 0.001).and significantly mediated the association between Qi-stagnation constitution and postpartum depressive symptoms (indirect effect = 0.36, 95% Bootstrap CI: 0.19–0.57).ConclusionIn summary, the qi-stagnation constitution emerges as a central risk factor for perinatal depressive symptoms, whereas the balanced constitution serves as a protective factor. Preterm birth and prenatal depressive symptoms are associated with an increased risk of postpartum depressive symptoms. These findings support integrating TCM constitution identification with depressive symptoms screening during early pregnancy. For women identified with a qi-stagnation constitution, a comprehensive strategy involving ‘constitution regulation and psychological intervention’ should be implemented to reduce the incidence of perinatal depressive symptoms. Further research should evaluate the effectiveness of these interventions in randomized controlled trials.