Changes in sleep quality, but not hormones predict time to postpartum depression recurrence.

Background: Poor sleep quality, dysregulation of hormones and increased inflammatory cytokines are all associated with the risk for postpartum major depression (PPMD). We evaluated change over time in sleep quality and hormones during the first 17 weeks postpartum, as well as a single cytokine measure, and their association with PPMD recurrence.
Methods: Participants were pregnant women (N=56), with past histories of MDD/PPMD but not depressed in their current pregnancy. The Pittsburgh Sleep Quality Index (PSQI) and blood samples were collected 8 times during the first 17 weeks postpartum. Estradiol, prolactin and cortisol, and a single measure of IL-6 were assayed. Recurrence was determined by two consecutive 21-item Hamilton Rating Scale for Depression (HRSD) scores≥15 and clinician interview.
Results: In the analyses of time to PPMD recurrence, poor sleep quality, but none of the hormones, was associated with PPMD recurrence (p<.05) after controlling for medication assignment. With every one point increase in PSQI scores across time, a woman's risk for recurrence increased by approximately 25% There was no significant association between PSQI scores and IL-6 concentrations in early postpartum (χ(2)=0.98, p=.32).
Conclusions: Poor sleep quality across the first 17 weeks post-delivery increases the risk for recurrent PPMD among women with a history of MDD. Changes in the hormonal milieu were not associated with recurrence. Further exploration of the degree to which poor sleep contributes to hormonal and cytokine dysregulation and how they are involved in the pathophysiology of PPMD is warranted.
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