Altered functioning of the HPA axis in depressed postpartum women

Abstract

Background: The present study aimed to evaluate the relationship between the functioning of the hypothalamic-pituitary-adrenal (HPA) axis and major depressive episodes in the remote postpartum period.

Methods: The sample (mean age, 28.0±5.3 years) consisted of 37 depressed postpartum women (DPP), 42 euthymic postpartum women (EPP) and 25 non-postpartum healthy women (HC). Salivary cortisol samples were collected immediately after awakening and 30min, 3 and 12h later, at approximately the sixth month postpartum (mean, 169.6±60.3 days).

Results: Differences in cortisol levels were observed at awakening (DPP<EPP=HC), at 30min (DPP<EPP<HC), at 3h (DPP=EPP<HC) and at 12h (DPP>EPP=HC). The relative increment in the cortisol awakening response (CARi%) was significantly higher in HC (113.5±94.3) than in EPP (63.1±69.8) and DPP (32.2±49.6). The relative reduction in diurnal variation (DVr%) was lower in DPP (56.5±41.8) than in EPP (75.6±22.4) and HC (75.1±13.0).

Limitations: The main limitation was cortisol collection on a single day and without measurement at midnight.

Conclusions: Our findings suggest that the remote postpartum period involves attenuation of HPA axis reactivity; this dysregulation is more pronounced in the presence of DPP, which is associated with a reduction in cortisol diurnal variation. Abnormalities in the neuroendocrine system related to stress processing, present even several months after delivery, can represent vulnerability to mental disorders. Thus, improvements in the mental health care of postpartum women are needed.

Keywords: Cortisol awakening response; Cortisol diurnal variation; Depression; Hypothalamic–pituitary–adrenal (HPA) axis; Postpartum; Puerperium.