The functioning of the hypothalamic-pituitary-adrenal (HPA) axis in postpartum depressive states: a systematic review.

Introduction: A large body of literature suggests the role of the hypothalamic-pituitary-adrenal (HPA) axis in postpartum depression (PPD). Nonetheless, these studies present discrepant methodology and results; thus, this hypothesis deserves further exploration. Areas covered: This review included studies investigating the HPA axis in PPD or postpartum blues published until November 2016. In total, 48 studies met the inclusion criteria. The HPA axis was mostly investigated in the immediate postpartum period (62.5%), and the majority of studies collected samples in the morning (43.8%), with one measure in a single day (43.8%), and blood was the fluid more often collected (58.4%). Seven out of 21 studies evaluating postpartum blues, and 15 out of 28 studies evaluating PPD detected abnormalities in the HPA axis functioning. Expert commentary: We found a significant heterogeneity in the methodology adopted by studies and consequently, in the results. Despite that, the majority of studies reported HPA changes in women with PPD during the remote period. Notably, reactivity tests pointed to attenuated HPA axis response. Ideally, future investigations should use validated reactivity tests, include larger sample sizes, consider many measures of cortisol throughout the day, and more than one day of collection. We also recommend that studies continue to use validated scales for mood assessment.