Hair as a Retrospective Calendar of Cortisol Production – Increased Cortisol Incorporation into Hair in the Third Trimester of Pregnancy

This study demonstrated that cortisol levels in human hair could serve as a retrospective calendar of cortisol production, particularly reflecting increased cortisol during the third trimester of pregnancy. The research involved 103 mothers with neonates, 19 mothers with toddlers aged 3-9 months, and 20 control women. Hair was segmented into 3-cm sections, representing growth over nine months. Results showed a significant decline in cortisol concentration from the scalp-near segment to the most distal segment, with n-Mothers having two-fold higher cortisol levels in the first segment compared to controls. However, no differences were found in subsequent segments. The study concluded that hair cortisol measurement could validly reflect increased cortisol production for up to six months, although the retrospective calendar might be limited to this period due to declining cortisol levels in adult hair.