0257 Testing the directionality of sleep and stress during the perinatal period: what's the impact on perinatal depression?
Authors: Dhaliwal Sammy , Gehrman Philip , Sharkey Katherine , Le Hyunh-Nhu 
Published: May 2022

Abstract

Introduction
Pregnancy is a time of pronounced sleep disturbance, with a majority (~85%) of women endorsing shorter, more fragmented sleep as gestation progresses. While new-onset antenatal depression (AND) is a known risk factor for postpartum depression, its etiology remains less understood, despite well-established evidence that incidence is the same among healthy first-time mothers as compared to women with established riskfactors inclusive of family or personal history of psychopathology. Heightened daily stress appraisals may be one critical pathway through which disrupted sleep gives rise to AND. The current study tested the directionality of the relationship between habitual nighttime sleep parameters and daytime stress ratings using a prospective amulatory field study design.

Methods
Fifty primiparous women (38% White; 32% Black; 30% Other race/ethnicity; mean age = 32 years, 28 weeks gestation) without a history of sleep disorders nor psychopathology completed 10-days (9-nights) of actigraphy and sleep diaries. They also engaged in 3-days of superimposed ecological momentary assessments (EMA) rating stress, positive, and negative affect at four intervals throughout the day. Analyses examined negative affective responses to social conflict and task-based demand througout days of EMA, at the within-person and between-women levels. Sleep variables explored included total sleep time (TST), sleep efficiency (SE; log-transformed), sleep onset latency (SOL) and sleep quality as measured by the Pittsburgh Sleep Quality Index. Cross-lagged hierarchical mixed models tested directionality of sleep-stress relationship. Time-varying covariates included time-of-day, previous day stress for sleep outcomes, and previous night sleep for stress outcomes, at the within-person levels.

Results
After days of greater stress (demand and conflict), women experienced significantly shorter, less efficient sleep and took longer to fall asleep (by both diary and actigraphy; [Beta(SE)=-6.3(1.4); 1.2(.12,), R^2=.27, .32, respectively; ps&lt;.01]. Following nights of shorter sleep, women endorsed greater negative affective responses to stress (Beta=.12, SE=.01, p&lt;.001; R^2=.27). Over the assessment period, women who had shorter, less efficient sleep experienced greater frequency, higher severity stressors, after adjusting for time-of-day, and baseline sleep characteristics, depression and anxiety levels (Betas = -7.4(2.6); .14(.01), ps&lt;.001, respectively). Given this bidirectional support, stress was examined as a moderator of the relationship between TST and depression severity at 34-36 weeks gestation, indicating that greater stress explained the relationship between shorter TST and heightened AND after adjustment for baseline measures.

Conclusion
This is the first study to explore directionality of sleep-stress relationships in a perinatal sample; results provide support for the idea that heightened daily stress engenders greater sleep disturbance (difficulty initiating and maintaining sleep; shorter duration). Bidirectional support for shorter sleep duration and increased stress appraisal was also found. The current project provides preliminary evidence for stress "spill-over" effects (i.e., stress transmission) as a potential mechanism for heightened antenatal depression symptoms.

Support (If Any)
NIMH 1R36MH118000-01, CTSI89431, SRS Mentor/Mentee Grant; T32 HL007713