Grant: Operating Grant

Recent studies suggest that pregnant women who report high levels of stress, anxiety, or depression have babies who are at increased risk for poor developmental outcomes. For example, infants of distressed mothers have a higher incidence of 'difficult' temperament, behavioural and emotional problems, and physical disease. Unfortunately, these effects can last a lifetime. Research also suggests that when women are stressed, anxious, or depressed during pregnancy, the way in which these psychological problems affect their babies is through 'stress hormones'. Exposure to maternal stress hormones during formation of the baby's stress response system can alter its function and make it over-reactive to stress throughout the child's life. These changes may explain why children whose mothers were distressed during pregnancy are at increased risk for developmental and health problems. The current proposal examines the biological processes that may cause changes in the development of babies born to stressed, anxious, or depressed mothers. The primary questions we address are: (1) does exposure to maternal stress hormones during gestation alter infants' stress responses? and (2), does the way a mother interacts with her infant after birth have the potential to change the effects of prenatal exposure to the mother's stress hormones? To address these questions, we repeatedly measure maternal cortisol during pregnancy and infant stress reactivity at 3 and 6 months of age. Given that the prevalence of harmful levels of stress, anxiety, and depression in expectant mothers is high (13%), understanding the association between maternal stress hormones and infant stress responses has the potential to influence policies aimed at reducing psychological distress in mothers in the prenatal and postpartum periods. Children and society stand to gain from reducing the health and developmental problems associated with exposure to maternal distress during pregnancy.