Sleep duration and C-reactive protein: Associations among pregnant and non-pregnant women.

Pregnant women experience more sleep disturbances and greater systemic inflammation than non-pregnant women. However, the few studies that have examined the links between sleep and inflammation in pregnant women have been in clinical samples. We examined whether sleep duration is associated with C-reactive protein (CRP) levels, a marker of inflammation, in pregnant and non-pregnant women in a population-based sample of US women. Participants were 2865 women of reproductive age (aged 20-44 years) in the National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of Americans. Sleeping <5 h on weeknights or workdays was significantly associated with increased CRP levels among both pregnant and non-pregnant women in unadjusted analyses; however, after adjustment for demographic, and health-related variables (depressive symptoms, self-rated health status, body mass index (BMI), diabetes), sleeping <5 h was no longer significantly related to CRP levels. Pregnant women had significantly higher CRP levels, after adjusting for sleep duration, demographic, and health-related variables. Our findings suggest that pregnancy is associated with increased peripheral CRP, after adjustment for sleep duration, demographic, and health factors. Further, in both pregnant and non-pregnant U.S. women of reproductive age, short sleep duration is associated with higher CRP levels, but this link is explained by self-rated health, BMI, and diabetes. Further studies are needed to investigate links of other sleep parameters (e.g., sleep fragmentation) with CRP in these populations.