Early origins of health disparities: material deprivation predicts maternal evening cortisol in pregnancy and offspring cortisol reactivity in the first few weeks of life.

OBJECTIVES Maternal hypothalamic pituitary adrenal-axis function regulates production of the stress hormone cortisol, which during pregnancy can cross the placenta and have lasting impacts on fetal growth and development. This article provides a preliminary test of the hypothesis that a woman's socioeconomic status (SES) predicts her cortisol during pregnancy and her offspring's cortisol during the early postnatal period among an ethnically diverse sample in Auckland, New Zealand to evaluate whether differences in cortisol contribute to the intergenerational inheritance of health disparities within this population. METHODS Maternal saliva samples were collected at waking and prior to sleep on 2 days in late pregnancy (34-36 weeks gestation; N = 55), and a subset of offspring saliva was collected before (N = 48) and 20 min after a standard vaccination at 6 weeks of age (N = 19). SES was quantified using a locally validated index of material deprivation, the NZ Deprivation Index for individuals (NZiDep). RESULTS We found that, after controlling for ethnicity and other covariates, women with higher NZiDep scores had significantly higher evening but similar morning cortisol, consistent with a pattern of chronic strain. Infants of women reporting greater material deprivation had elevated cortisol response to vaccination. CONCLUSIONS These findings suggest that maternal SES experience impacts maternal cortisol in pregnancy and offspring cortisol reactivity soon after birth, with potential long-term effects on offspring biology and health. Additional research is needed to clarify how biological and behavioral factors in both the prenatal and postnatal period facilitate this relationship.