Giesbrecht, GeraldLetourneau, NicoleCampbell, Tavis, S.2016-12-012016-12-012016-07-18Giesbrecht, G.F., Letourneau, N., Campbell, T. & the APrON Study Team. Sexually Dimorphic and Interactive Effects of Prenatal Maternal Cortisol and Psychological Distress on Infant Cortisol Reactivity. Development and Psychopathology (2016 in press), doi:10.1017/S0954579416000493.http://hdl.handle.net/1880/51759Article deposited according to publisher policies: https://www.cambridge.org/core/services/open-access-policiesIn utero exposure to maternal psychological distress is a risk factor for developmental psychopathology and these effects are believed to occur, in part, via dysregulation of the maternal and fetal hypothalamic-adrenal-pituitary (HPA) axes. Nevertheless, only a few human studies have directly assessed the effects of prenatal cortisol exposure on infant cortisol reactivity and none have investigated sex differences or potential interactions between prenatal cortisol and psychological distress. Here we report on a prospective longitudinal investigation (N=236) of in utero exposure to maternal cortisol and distress in a relatively high SES and low risk population to determine whether these exposures interact in their effects on infant (M age=3.0 months; Range=2.3-5.0; 51.9% male) cortisol reactivity and whether there are sex differences in these effects. Results revealed both sexually dimorphic and interactive effects of prenatal cortisol and distress, even after controlling for postnatal distress. In general, blunted reactivity in females was associated with exposure to high maternal distress and flattened patterns of diurnal maternal cortisol whereas blunted reactivity in males was associated with exposure to steeper morning increases and daytime decreases in maternal cortisol. The findings suggest that sex differences in the effects of prenatal cortisol and distress on infant cortisol reactivity are a plausible mechanism by which maternal experiences during pregnancy contribute to sex differences in the development of psychopathology.enjournal article10.11575/PRISM/33657