Trends in hair cortisol from preconception to the postpartum period

Cortisol is a biological marker of stress, and its levels reflect the hypothalamic-pituitary-adrenal (HPA) axis response to stress over time. Saliva, blood, and urine cortisol reflect acute stress, whereas assessment of hair cortisol is a better reflection of chronic stress. There is limited information on hair cortisol concentration (HCC) in the perinatal period, particularly, in the preconception and postpartum periods. In addition to being a biomarker for stress, high levels of cortisol are typically associated with poor psychosocial outcomes, and adverse pregnancy outcomes. The objectives of this study were: (1) to measure HCC from six months preconception to six months postpartum; (2) to examine the relationship between HCC and demographic characteristics, depressive symptoms, and perceived stress in the first six months postpartum period; (3) and to assess the associations between HCC and systemic inflammatory markers in the first six months postpartum. The analysis included 96 women from a longitudinal study with up to 3 study visits in the first six months postpartum. Blood and hair samples were collected at 1–2 months (PP1), 3–4 months (PP2), and 5–6 months (PP3) postpartum. We obtained sociodemographic information, depressive symptoms, and perceived stress scores at PP1-PP3. To quantify cortisol levels over time, 8 segments were derived corresponding to 6 (PC1) and 3 (PC2) months preconception as well as for each trimester (T1-T3) and postpartum (PP1-PP3). Eight cytokines (Granulocyte-macrophage colony-stimulating factor (GM-CSF), Interferon- gamma [IFN- γ], Interleukin [IL]-10, IL-2, IL-4, IL-6, IL-8, and Tumor necrosis factor-alpha (TNF- α) were measured in plasma in the postpartum samples. Univariate, bivariate, correlations, and linear mixed modelling were performed using SAS 9.4. Multiple testing correction was conducted for correlations using false discovery rate and a Q value of