[Show abstract][Hide abstract] ABSTRACT: Background . The postpartum period is a crucial and demanding time for new mothers to perform infant care, personal, household, occupational, social, and community activities. However, disturbances in circadian motor activity related to nighttime infant care may present significant challenges in performing normal day-to-day functional tasks. The presence of postpartum depression (PPD) may even further compromise functioning during this critical time. Further, increased nighttime motor activity related to infant care may precipitate or worsen depressive symptoms. Although it is recognized that significant alterations in functional status and circadian motor activity are associated with depression in the general population, there is minimal data about functional status and circadian motor activity among women with PPD. Methods and results . A two-group longitudinal panel design was used to determine the difference in functional status and circadian motor activity between 23 women with and 23 women without PPD who were 6 to 26 weeks postpartum. The Inventory of Functional Status After Childbirth measured functional status. Wrist actigraphy measured circadian motor activity during a 7-day data collection period. The results of this study suggest that women with PPD experience significantly lower functioning but similar circadian motor activity patterns compared to women without PPD. However, women with PPD demonstrated poorer sleep quality and were 12 times less likely to return to full functional status than women without PPD. Finally, results of this study suggest that women with PPD, unlike major depression, demonstrate a unique hierarchy of levels of domains of functional status, in which infant care takes precedence over other areas of functioning. Conclusions . Comprehensive postpartum care should include questions about sleep quality and daily functioning in order to fully address the needs of women with PPD. Areas for future research include evaluating incorporation of functional status measurement into current PPD assessment tools and evaluating its use in monitoring treatment progress; finding relevant interventions to address poor sleep quality and low functioning; and repeating the study with larger and more diverse samples in order to verify the findings of this study.