Investigating the relationship between sleep and postpartum depression: a longitudinal study examining the relationships between subjective and objective sleep during the perinatal period and postpartum depression.

Abstract

Research has suggested that a bi-directional relationship exists between sleep disruption and depression. Not only is poor sleep a commonly reported symptom in those with depression, some aspects of sleep have also been shown to predict the onset of depression. Despite sleep problems being a commonly reported occurrence throughout the perinatal period, the field of perinatal sleep research remains in its relative infancy. However, recent studies suggest that sleep disturbances during this time may increase the risk of developing postpartum depression. Currently, research in this area is limited by studies that have failed to control for depressive symptoms at baseline, relied upon subjective, often retrospective, measures of sleep, and have only measured symptoms of postpartum depression in the early postpartum period. Few studies have used polysomnography, considered the ‘gold standard’ of sleep, and no studies to date have specifically compared the relationship between subjective and objective sleep. Therefore, the major aim of this thesis was to gain a better understanding of the specific aspects of sleep that were most relevant to postpartum depression. In order to address this aim, studies were carried out to: explore the aspects of sleep most relevant to major depressive disorder; examine differences in sleep between pregnant and non-pregnant women; investigate the relationships between subjective and objective measures of sleep; explore longitudinal changes in sleep, fatigue and depression throughout the perinatal period, and finally; examine which aspects of sleep at which time-point were most relevant to the development of postpartum depression. Overall this thesis found that women experience significant changes to their sleep throughout the perinatal period. While the sleep of third trimester women is considerably poorer than that of non-pregnant women (both objectively and subjectively), the most significant changes occur in the transition between late pregnancy and the early postpartum period. Furthermore, increased amounts of sleep and reports of difficulty falling asleep during late pregnancy predicted the development of postpartum depressive symptoms. This suggests that certain aspects of sleep during late pregnancy may serve as markers for women at risk of developing postpartum depression.