Maternal Influence on Child HPA Axis: A Prospective Study of Cortisol Levels in Hair

The study investigated cortisol levels in hair as a biomarker of prolonged stress in 100 children and their mothers, with repeated measures at ages 1, 3, 5, and 8 years. Results showed that maternal hair cortisol during pregnancy correlated with child hair cortisol at ages 1 and 3. Child cortisol levels decreased over time but remained correlated at successive ages. High hair cortisol levels were associated with birth weight, nonappropriate size for gestational age, and living in an apartment. The findings suggested a heritable trait or maternal influence on the child's stress response system, indicating that hair cortisol concentration could be a useful noninvasive biomarker for prolonged stress in children.