Sleep and depression in postpartum women: a population-based study

Abstract

Study objectives: (1) To describe the prevalence of and risk factors for postpartum maternal sleep problems and depressive symptoms simultaneously, (2) identify factors independently associated with either condition, and (3) explore associations between specific postpartum sleep components and depression.

Design: Cross-sectional.

Setting: Population-based.

Participants: All women (n = 4191) who had delivered at Stavanger University Hospital from October 2005 to September 2006 were mailed a questionnaire seven weeks postpartum. The response rate was 68% (n = 2830).

Interventions: None.

Measurements and results: Sleep was measured using the Pittsburgh Sleep Quality Index (PSQI), and depressive symptoms using the Edinburgh Postnatal Depression Scale (EPDS). The prevalence of sleep problems, defined as PSQI > 5, was 57.7%, and the prevalence of depression, defined as EPDS > or = 10, was 16.5%. The mean self-reported nightly sleep duration was 6.5 hours and sleep efficiency 73%. Depression, previous sleep problems, being primiparous, not exclusively breastfeeding, or having a younger or male infant were factors associated with poor postpartum sleep quality. Poor sleep was also associated with depression when adjusted for other significant risk factors for depression, such as poor partner relationship, previous depression, depression during pregnancy and stressful life events. Sleep disturbances and subjective sleep quality were the aspects of sleep most strongly associated with depression.

Conclusions: Poor sleep was associated with depression independently of other risk factors. Poor sleep may increase the risk of depression in some women, but as previously known risk factors were also associated, mothers diagnosed with postpartum depression are not merely reporting symptoms of chronic sleep deprivation.

Figure 1

Changes in mean PSQI score and subscores by postpartum week. —PSQI total score* ------- Sleep efficiency, subscore 4* _ _ _ Sleep duration, subscore 3* PSQI - Pittsburgh Sleep Quality Index. Reduced scores indicate better global sleep quality, better sleep efficiency, and longer sleep duration. Error bars: 95% confidence interval. *Significant change (P < 0.01, linear regression). The PSQI subscores 1: Subjective sleep quality, 2: Sleep onset latency, 5: Sleep disturbances, 6: Sleep medication and 7: Daytime dysfunction did not show significant changes by postpartum week, and are not shown.

Figure 2

Prevalence of depression (EPDS ≥ 10) by PSQI scores and parity. EPDS – Edinburgh Postnatal Depression Scale. PSQI – Pittsburgh Sleep Quality Index (Range 0-21). Error bars – 95% confidence interval.