Background <p>Postpartum depression is a significant mental health disorder that can have profound and detrimental effects on both the mother and child. Early intervention, facilitated by a comprehensive understanding of the risk factors associated with this condition, is crucial for mitigating the onset of postpartum depressive symptoms.</p> Methods <p>The aim of this prospective cohort study was to examine the effects of time perspective and circadian rhythm disturbances on postpartum depressive symptoms. Participants were examined in the first trimester of pregnancy and during the first 3 months after delivery. A total of 157 women were recruited. Of these, 126 participants successfully completed both stages of the study. At each stage, the women completed questionnaires—the Zimbardo Time Perspective Inventory, the Dark Future Scale, the Biological Rhythms Interview for Assessment in Neuropsychiatry, and the Edinburgh Postpartum Depression Scale. The participants also wore an actigraphy monitor for 1 week.</p> Results <p>The results showed that fatalistic time perspective, subjectively perceived disturbances of circadian rhythms, and a tendency to focus on a negative future in the first trimester were associated with increased postpartum depressive symptoms. Moreover, the association of fatalistic and future negative perspectives with postpartum depressive symptoms was statistically mediated by the perception of disturbances of circadian rhythms. There were no significant relationships between objective and self-report measures of circadian rhythm disturbances.</p> Conclusions <p>The findings of the present study highlight the need for future preventive research on postpartum depression symptoms to assess time perspective and perceived circadian rhythm disturbances among women in early pregnancy.</p>