Attachment Style and Perinatal Depressive Symptoms Across the Perinatal Period in Japan

<b>Background/Objectives:</b> Perinatal depressive symptoms are influenced by psychosocial and relational factors. This study examined stage-specific associations between adult attachment style, psychological stress responses, satisfaction with the childcare environment, and depressive symptoms across five perinatal stages in Japan. <b>Methods:</b> This repeated cross-sectional study included 417 independent assessment datasets collected during the first, second, and third trimesters, and at two weeks and one month postpartum. Depressive symptoms were assessed using the Edinburgh Postnatal Depression Scale (EPDS). Adult attachment was measured using the Relationship Questionnaire, and psychological stress responses were measured using the Stress Response Scale-18 (SRS-18). Salivary cortisol was analyzed in a subset of participants. <b>Results:</b> Elevated depressive symptoms (EPDS+) were observed in approximately 10-15% of participants across stages. Attachment insecurity was associated with higher odds of EPDS+ at one month postpartum (OR 12.1, 95% CI 1.35-109). Higher SRS-18 scores were consistently associated with increased odds of EPDS+ across stages (e.g., OR 20.9, 95% CI 5.46-80.0 in the second trimester). Lower satisfaction with the childcare environment was associated with elevated depressive symptoms during pregnancy. No consistent association was observed between salivary cortisol and EPDS+. <b>Conclusions:</b> Adult attachment insecurity and psychological stress responses were associated with perinatal depressive symptoms across stages. By clarifying stage-specific psychosocial patterns, these findings support stress-attachment frameworks, suggesting that attachment insecurity may heighten vulnerability during the perinatal transition, provide culturally specific evidence from Japan, and underscore the potential value of brief psychosocial screening in routine perinatal care.