A consensus of research has demonstrated that stress and adversity can become embodied and transmitted across generations, creating pathways by which social and economic inequality can affect human biology and health for decades. Most research has identified fetal development as a sensitive period for this transmission of stress from mother to child, with considerably less research on the postnatal period. Maternal postnatal stress has been found to shape infant stress response development, potentially creating a pathway by which maternal stress can become embodied in the next generation and influence how the next generation responds to and handles stressors. However, it is not clear how these effects on the stress response become embodied and whether these changes persist through childhood. This study proposes to test whether maternal postnatal stress in her child’s infancy and toddlerhood is related to the child’s methylation of stress-response related genes at age 7.

Similarly, previous research has demonstrated a relationship between psychosocial stress and childhood growth in weight and height. However, this relationship has been inconsistently demonstrated and the pathways by which stress affects growth are not clear. While the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in this relationship, results have been inconsistent. This research project proposes to test the relationship between growth velocity throughout childhood and methylation of HPA-axis related genes at age 7, in order to determine whether alterations to stress response physiology are a mechanism by which stress can affect growth.