Salivary cortisol during memory encoding in pregnancy predicts postpartum depressive symptoms: a longitudinal study

Postpartum depression (PPD) is a common disorder that substantially decreases quality of life for both mother and child. In this longitudinal study, we investigated whether emotional memory, salivary cortisol (sCORT) or alpha-amylase during pregnancy predict postpartum depressive symptoms.

Forty-four pregnant women (14 euthymic women with a diagnosis of major depressive disorder [MDD] and 30 healthy women) between the ages of 19 and 37 years (mean age = 29.5±4.1 years) were longitudinally assessed in the 2nd trimester of pregnancy (12-22 weeks of gestational age) and again at 14-17 weeks postpartum. Depressive symptoms were assessed using the Edinburgh Postnatal Depression Scale (EPDS).

Follow-ups were completed for 41 women (7% attrition). Postpartum EPDS scores were predicted by sCORT collected immediately after an incidental encoding memory task during pregnancy (b=-0.78, t -2.14, p=0.04). Postpartum EPDS scores were not predicted by positive (p=0.27) or negative (p=0.85) emotional memory.

The results of this study indicate that higher levels of sCORT during a memory encoding task in the 2nd trimester of pregnancy are associated with lower postpartum EPDS scores. While the hypothalamus-pituitary-adrenal (HPA) axis has long been associated with the neurobiology of MDD, the role of the HPA axis in perinatal depression deserves more attention.