Browsing by Author "Thomas, Jenna"

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    Developmental Origins of Infant Emotion Regulation: Mediating and Moderating Effects of Infant Temperament and Maternal Sensitivity
    (2015-09-23) Thomas, Jenna; Campbell, Tavis; Giesbrecht, Gerald
    The current study examined perinatal factors that impact infant emotion regulation (ER) development. Prenatal depression, generalized anxiety, pregnancy-specific anxiety (PSA), and diurnal cortisol levels were assessed in 256 pregnant women in early and late pregnancy. Infant temperamental negativity was assessed at 3 months, and observational measures of infant ER during frustration and maternal sensitivity were assessed at 6 months. Results revealed that PSA had a positive direct effect on infant ER, which potentially indicated emotional over-regulation in these infants. PSA also had a negative indirect effect on infant ER through increased temperamental negativity, which was dependent on levels of maternal sensitivity. Specifically, infants with high negativity demonstrated emotional under-regulation, but only when their mother displayed low levels of sensitivity. The study identified two pathways by which PSA may result in long-term changes in infant emotional development. Implications for future research and intervention planning are discussed.
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    Prenatal bisphenol a exposure and dysregulation of infant hypothalamic-pituitary-adrenal axis function: findings from the APrON cohort study
    (2017-05-19) Giesbrecht, Gerald F; Ejaredar, Maede; Liu, Jiaying; Thomas, Jenna; Letourneau, Nicole; Campbell, Tavis; Martin, Jonathan W; Dewey, Deborah
    Abstract Background Animal models show that prenatal bisphenol A (BPA) exposure leads to sexually dimorphic disruption of the neuroendocrine system in offspring, including the hypothalamic-pituitary-adrenal (HPA) neuroendocrine system, but human data are lacking. In humans, prenatal BPA exposure is associated with sex-specific behavioural problems in children, and HPA axis dysregulation may be a biological mechanism. The objective of the current study was to examine sex differences in associations between prenatal maternal urinary BPA concentration and HPA axis function in 3 month old infants. Methods Mother-infant pairs (n = 132) were part of the Alberta Pregnancy Outcomes and Nutrition study, a longitudinal birth cohort recruited (2010–2012) during pregnancy. Maternal spot urine samples collected during the 2nd trimester were analyzed for total BPA and creatinine. Infant saliva samples collected prior to and after a blood draw were analyzed for cortisol. Linear growth curve models were used to characterize changes in infant cortisol as a function of prenatal BPA exposure. Results Higher maternal BPA was associated with increases in baseline cortisol among females (β = 0.13 log μg/dL; 95% CI: 0.01, 0.26), but decreases among males (β = −0.22 log μg/dL; 95% CI: -0.39, −0.05). In contrast, higher BPA was associated with increased reactivity in males (β = .30 log μg/dL; 95% CI: 0.04, 0.56) but decreased reactivity in females (β = −0.15 log μg/dL; 95% CI: -0.35, 0.05). Models adjusting for creatinine yielded similar results. Conclusions Prenatal BPA exposure is associated with sex-specific changes in infant HPA axis function. The biological plausibility of these findings is supported by their consistency with evidence in rodent models. Furthermore, these data support the hypotheses that sexually dimorphic changes in children’s behaviour following prenatal BPA exposure are mediated by sexually dimorphic changes in HPA axis function.