Abstract
BACKGROUND: Suicidal thoughts occur in up to one third of pregnant women. Suicidal ideation (SI) has been linked to hypothalamic-pituitary-adrenal (HPA) axis dysregulation in other populations and could underlie SI during pregnancy when the HPA axis undergoes gestational transformation. However, no studies have evaluated the HPA axis in prenatal suicide risk, including regulation of cortisol. We examined whether SI is associated with distinct features of cortisol regulation among women during the 3(rd) trimester of pregnancy. METHODS: Sixty-four women completed measures of SI and provided 8 saliva samples across 2 consecutive days for cortisol assay. Three cortisol metrics were assessed in separate linear regression models (awakening response, diurnal slope, and area under the curve), along with selected covariates. RESULTS: Women with SI (n=10) had a dampened diurnal cortisol slope in contrast to other women (β (=) -.32, p =.005; ηp2 =.094). Cortisol levels decreased from waking to 45 minutes after waking (.33ug/dL to .27ug/dL) rather than increasing as found for women without SI (.38ug/dL to .51ug/dL). Their cortisol also rose from 4pm to sleep (.09ug/dL to .31ug/dL) in contrast to a decrease among women without SI (.12ug/dL to .09ug/dL; F = 6.26 (4,59), p=.015). LIMITATIONS: The small number of women with SI may have reduced the power to detect significant effects. CONCLUSIONS: Findings for women with SI differ from the expected pattern of cortisol secretion across the day and indicate circadian rhythm dysfunction. Further research can build on these results to clarify mechanisms underlying perinatal suicidality, with improved assessment and intervention targets as the goal.