Relationship between inflammatory biomarkers and depressive symptoms during late pregnancy and the early postpartum period: a longitudinal study

Objective: Perinatal depressive symptoms often co-occur with other inflammatory morbidities of pregnancy. The goals of our study were 1) to examine whether changes in inflammatory markers from the third trimester of pregnancy to 12 weeks postpartum were associated with changes in depressive symptoms; 2) to examine whether third trimester inflammatory markers alone were predictive of postpartum depressive symptoms; and 3) to examine the relationship between inflammatory markers and depressive symptoms during the third trimester of pregnancy and at 12 weeks postpartum. Methods: Thirty-three healthy pregnant women were recruited from the Women's Health Concerns Clinic at St. Joseph's Healthcare in Hamilton, Canada. The impact of depressive symptoms on the levels of interleukin (IL)-6, IL-10, tumor necrosis factor alpha (TNF-alpha), and C-reactive protein (CRP) at the third trimester of pregnancy, at 12 weeks postpartum, and across time was assessed using linear and mixed-model regression. Results: Regression analysis revealed no significant association between depressive symptoms and any of the candidate biomarkers during pregnancy, at 12 weeks postpartum, or over time. Pregnancy depressive symptoms (p > 0.001), IL-6 (p = 0.025), and IL-10 (p = 0.006) were significant predictors of postpartum Edinburgh Perinatal Depression Scale (EPDS) score. Conclusions: Our study supports previous reports from the literature showing no relationship between inflammatory biomarkers and depressive symptoms during late pregnancy, early postpartum, or across time. Our study is the first to observe an association between late pregnancy levels of IL-6 and IL-10 and postpartum depressive symptoms. Further studies with larger samples are required to confirm these findings.