Circadian rhythm and sleep are related to health, but there is little data on the relationship between the sleep/wake rhythm and mood at different stages of pregnancy. The aim of this prospective, longitudinal study was to investigate the associations of circadian rhythm and sleep disruptions with stress and depression among women in early and late pregnancy. The participants were 26 pregnant women. Objective and subjective estimations of circadian rhythm and sleep were administered, namely actigraphy and the Biological Rhythms Interview of Assessment in Neuropsychiatry in the form of a questionnaire. The Perceived Stress Scale and the Edinburgh Postnatal Depression Scale were also used. Subjectively perceived circadian rhythm disruptions were positively related to stress. Tendency to maintain a regular rhythm of sleep and activity in early pregnancy and subjectively perceived disruptions of circadian rhythms in late pregnancy were positively associated with prenatal depression in late pregnancy. Sleep fragmentation and long time spent in bed at night in early pregnancy were positively associated with stress and depression in late pregnancy. The results suggest the importance of flexibility and the ability to adapt one's circadian activities to the demands of the situation of pregnancy-related changes in lifestyle. They also indicate the significance of good-quality uninterrupted night sleep in early pregnancy.
Keywords: Circadian rhythms; actigraphy; pregnancy; prenatal depression; sleep; stress.