A systematic review of associations between hormone levels in hair and peripartum depression.

Peripartum depression is a global health concern, characterized by mood disturbances inclusive of pregnancy through up to 12-months postpartum. Hormones play a vital role in pregnancy maintenance, fetal development, and labor and delivery and change significantly as a function of pregnancy and childbirth. However, such life sustaining changes may have consequences related to risk for peripartum depression. To date, most studies that have examined hormones in relation to peripartum depression have focused on blood or saliva sampling approaches, though hair analysis offers unique information on trajectories of hormone concentrations over more sustained periods of time (i.e., over months). The aim of this systematic review was to provide a comprehensive review of the association between hair measures of hormones (i.e., cortisol, progesterone, estrogen, and testosterone) and depression during the peripartum period. Forty-one studies were identified for inclusion. A majority of studies reported statistically null associations. Between-person studies varied widely in reported direction and magnitude of hair hormone-depression associations, most likely attributable to a wide range of methodological approaches including timing of assessments and sample size. Studies using within-person approaches observed positive coupling of cortisol concentration and symptoms across time. Most studies focused exclusively on cortisol. We recommend future research consider both stress and reproductive hormones, prioritize within-person change in hormone levels given this is a period of dramatic change, and include contextual (e.g., social support, adverse and benevolent childhood experiences, physical and psychiatric conditions) features that may modify both changes in hormones and the association between hormone levels and depression in the peripartum period.