Evolved birth physiology meets modern birth practice: Sustained effects of planned cesarean delivery on child hair cortisol in Brazil.

ABSTRACT: Cesarean section (CS) is the most common major surgery worldwide and, by enabling birth outside physiologic labor, is an evolutionary novelty. Labor-related mechanical and hormonal stimuli, shaped by natural selection, facilitate neonatal adaptation to extrauterine life. While prior work has emphasized the biological impacts of altered microbial exposure following CS, the developmental implications of missing labor are less explored. We evaluated whether birth without labor was associated with differences in child hair cortisol, an integrated measure of hypothalamic-pituitary-adrenal activity that influences growth, metabolism, immunity, and behavior. Using longitudinal data from singleton births in the 2015 Pelotas Birth Cohort in Brazil ([Formula: see text] observations from 3,537 partic

SUBMITTER: Thayer ZM 

PROVIDER: S-EPMC12718353 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature