PurposeTo determine whether conventional treatment and assisted reproductive technology for infertility are associated with depressive symptoms and to identify the predictors of depressive symptoms during the first 6 months' post‐partum.MethodsA prospective cohort design was used, with the participants being recruited from 13 Japanese hospitals. Using self‐report questionnaires, a total of 2709 women (response rate: 71.9%) provided longitudinal data at five time points: during their hospital stay and at 1, 2, 4, and 6 months' post‐partum. The depressive symptoms were measured by using the Japanese version of the Edinburgh Postnatal Depression Scale (EPDS). A logistic regression analysis was used to examine the association between the mode of conception and depressive symptoms and to identify the predictors of the depressive symptoms.ResultsThere was no significant association between the mode of conception and the depressive symptoms at any time point. Six factors that were associated with the EPDS score were first‐time childbirth, emergency cesarean delivery, infant feeding, financial burden, having a male infant, and dissatisfaction with social support.ConclusionThere was no significant relationship between the mode of conception and depressive symptoms. Nursing care should be based on individual assessments that focus on parity, the delivery method, infant feeding method, financial burden, the infant's sex, and social support, rather than on the mode of conception.