Associations between psychological distress and hair cortisol during pregnancy and the early postpartum: A meta-analysis

Background Pregnancy and the early postpartum signify a period of high stress. Perinatal stress can include psychological distress (PD), such as anxiety, depression, and stress, as well as neuroendocrine stress, indexed by activation of the hypothalamic-pituitary-adrenal (HPA) axis and the production of cortisol. Elevated PD and cortisol levels during the perinatal period can have long-term implications for the mother and child. Despite knowing that PD and HPA activity during the perinatal period independently impact health and development, research to date is unclear as to the association between PD and maternal hair cortisol. Methods The present meta-analysis included 27 studies to assess the strength of the relation between PD and hair cortisol levels during pregnancy and early postpartum. Several sample and methodological factors were assessed as moderators. Analyses were conducted using multilevel meta-analysis. Results The overall effect size between PD and HCC was small and not significant z = 0.044, 95% CI [-0.001, 0.089]. Moderator analyses indicated that the strength of the association between PD and hair cortisol was moderated by pregnancy status (i.e., effects were stronger in pregnant compared to postpartum samples), timing of HCC and PD measurements (i.e., effects were larger when PD was measured before HCC) and geographic location (i.e., effects were larger in North American studies). Conclusion The findings advance our understanding of the link between PD and HPA activity during the perinatal period, and further underscores the need for longitudinal work to better understand this relationship during a critical developmental period.