Associations of prenatal and perinatal factors with cortisol diurnal pattern and reactivity to stress at preschool age among children living in poverty

Objective: To examine the association of pre- and perinatal factors with diurnal cortisol pattern and reactivity to a stressor at preschool age among children living in poverty. Methods: Preschool aged children (n=275) provided saliva samples 3 times per day for 3 days to assess circadian rhythmicity (intercept and slope reflected diurnal pattern) and during a behavioral stress elicitation protocol to measure reactivity (5 samples before, during and after the stressor). Pre- and perinatal predictors were pregnancy weight gain, pre-pregnancy body mass index (BMI), infant birth weight z-score and gestational age. We ran 7 linear regression models predicting each of the cortisol outcomes including all pre-and perinatal predictors and covariates simultaneously. Results: Greater pregnancy weight gain predicted higher morning cortisol [β=0.020 (SE 0.007), p=0.003]. Greater pregnancy weight gain also predicted higher cortisol at recovery from the stressor in girls only [β=0.002 (SE 0.001), p=0.036]. There was no association of pre-pregnancy BMI with any cortisol outcome. Higher birth weight z-score predicted higher morning cortisol in the total sample [β=0.134 (SE 0.066, p=0.043]. Greater gestational age predicted lower cortisol during peak stress in the sample who underwent cortisol reactivity testing [β=-0.015 (SE 0.007), p=0.032] and in boys [β=-0.032 (SE 0.014), p=0.027]. Conclusion: Pre- and perinatal factors are associated with cortisol patterning in offspring at preschool age. The implications for child health require additional studies.