Abstract
Given high health costs of depression during pregnancy and the first postnatal year, it is important to understand mechanisms involved in the emergence and perpetuation of symptoms during this time. In a series of 2 studies, we aim to clarify bidirectional relations between mothers' physiological stress regulation-stress-related activation of the hypothalamic-pituitary-adrenal (HPA) axis-and their course of depressive symptoms. In Study 1, 230 pregnant women recruited from a women's mental health program gave 3 saliva samples in the context of psychosocial stress at 24, 30, and 36-weeks gestation. They self-reported depressive symptoms across the three trimesters of pregnancy and first year postpartum. Multilevel models revealed women with elevated salivary cortisol during pregnancy showed a course of escalating ante- and postnatal symptoms, implicating HPA hyperactivation as a precursor to worsening mood problems. In Study 2, 54 mothers from a community sample self-reported depressive symptoms at 3, 6, 12, and 18 months postnatal. At 18 months, they participated in a dyadic stress task with their infant and gave 4 saliva samples for cortisol assay. For mothers with a lifetime depression diagnosis, an escalating course of postnatal symptoms predicted a higher, flatter cortisol response profile. Together, the results of these studies suggest that for high-risk mothers, a trajectory of worsening depression may both follow from and give rise to neuroendocrine stress hyperactivation. These findings suggest greater attention is warranted to course of depressive symptoms across the ante- and postnatal period, rather than symptom levels at any given time, to characterize health risks.
General Scientific Summary
Research on the mechanisms perpetuating antenatal and postnatal depression has been limited by a focus on symptoms at a given time, rather than the course of symptoms over time. In a series of two independent but complementary studies, we investigated bidirectional associations between the course of mothers' ante- and/or postnatal depressive symptoms and their hypothalamic-pituitary-adrenal (HPA) axis activation during stress. In Study 1, we showed that women's prenatal HPA hyperactivation predicted escalating depressive symptoms from pregnancy through the first postpartum year, and in Study 2 we found that escalating postnatal depressive symptoms among mothers with a lifetime depression diagnosis predicted HPA hyperactivation during interactions with their infants; together, these findings support a role of HPA dysregulation in perpetuating depressive symptoms among at-risk mothers.
