Toddler hair cortisol levels are associated with maternal prenatal depression.

Objectives: Cortisol is an important metabolic hormone that regulates multiple physiologic systems. Cortisol metabolism is sensitive to early life environments, including that experienced prenatally. Limited research has evaluated factors that predict variation in maternal and offspring toddler hair cortisol, which is important since hair cortisol represents different dynamics of hypothalamic pituitary adrenal (HPA)‐axis function than more common salivary or serum measures. Methods: To address this gap, we longitudinally evaluated whether maternal depression measured in pregnancy and 1 month postnatal was associated with maternal and offspring hair cortisol levels approximately 15 months after birth (n = 46 mothers, 40 toddlers; mean 15.6 months postnatal, SD = 2.9 months). Results: Mean depression symptoms were highest during the prenatal period. Prenatal, but not postnatal, maternal depression was associated with offspring hair cortisol levels (B = 0.095, p =.01). Maternal hair cortisol was not associated with depression measured at either time point. Conclusions: These findings indicate that offspring hair cortisol more than a year after birth is associated with maternal prenatal depression, consistent with previous research in salivary cortisol, suggesting that long‐term offspring stress physiology may be influenced by conditions experienced in utero. These findings highlight the potential for hair cortisol—a minimally invasive and easy‐to‐collect measure— to index toddler HPA‐axis dynamics. [ABSTRACT FROM AUTHOR]