Oestradiol and Progesterone Variability in Adolescent Females: Associations with Brain Structure and Mental Health Problems

ObjectiveAdolescent females are at increased risk for adverse mental health problems, and puberty is thought to be a critical factor. Pubertal onset involves substantial variability in oestradiol (E2) and progesterone (P4), yet the impact of these hormone dynamics remains unclear. We investigated whether within-individual E2 and P4 variability across one month relates to brain structure and mental health problems in adolescent females. MethodsParticipants were 147 females (11-17 years) from the community-based, cross-sectional Puberty and NeuroDevelopment in Adolescents (PANDA) study in Australia. Salivary E2 and P4 were collected weekly for one month, with variability indexed as within-subject standard deviation. Structural MRI was acquired on the final sampling day. Mental health problems were assessed via self- and parent-report. Linear regression and mediation analyses tested associations between hormone variability, brain structure, and mental health, adjusting for demographics. ResultsGreater P4 variability was associated with smaller left thalamus volume (Cohens d = -0.26, pFDR = 0.031). Higher E2 variability was associated with fewer anxiety (d = -0.170, pFDR = 0.043) and depressive symptoms (d = -0.179, pFDR = 0.036), lower emotion dysregulation (d = -0.179, pFDR = 0.036), and smaller right hippocampus volume in pre-menarchal adolescents (d = -0.192, p = 0.02). Weekly reductions in E2 predicted lower positive affect (d = 0.084, p = 0.048). ConclusionThese findings indicate that hormone variability may meaningfully shape brain and behavioural development in adolescent girls differently from hormone-related transitions in adulthood. Larger, replicable, and longer-term studies are needed to confirm these patterns. Oestradiol and Progesterone Variability in Adolescent Females: Associations with Brain Structure and Mental Health Problems. Muskan Khetan 1, Ye Ella Tian 2, Nandita Vijayakumar 3,4, Sarah Whittle 1,4 O_LICentre for Youth Mental Health, University of Melbourne, Australia C_LIO_LIDepartment of Psychiatry, University of Melbourne, Australia C_LIO_LIMurdoch Childrens Research Institute, Australia C_LIO_LISchool of Psychology, Deakin University, Australia C_LI