Oestradiol dynamics after polytrauma are linked to injury severity and adverse outcomes.

Introduction: Women show lower mortality and fewer complications than men after severe polytrauma, but underlying mechanisms remain unclear. In this context, reproductive hormones have gained increasing attention. In particular, oestradiol is controversially discussed: experimental studies suggest protective effects, whereas clinical studies link elevated levels to systemic inflammation and adverse outcomes. Methods: Therefore, in this prospective cohort study, patients with polytrauma(injury severity score ≥16) were enrolled. Hormones (oestradiol, progesterone, testosterone, luteinising hormone [LH], follicle-stimulating hormone [FSH]) were measured on admission and daily on days 1-5. Longitudinal changes were analysed with repeated-measures models. Associations with injury severity and clinical outcomes (organ failure, length of stay, mortality) were assessed using correlation and regression analyses adjusted for relevant confounders. Results: 128 patients, progesterone, testosterone, LH, and FSH declined significantly over time, whereas oestradiol showed an early rise with a peak around the second day followed by a decline. Sex-specific differences were observed for testosterone, LH, and FSH, but not for oestradiol. Elevated oestradiol levels and post-traumatic increases were independently associated with injury severity and adverse outcomes, including organ failure, longer stay and mortality, after adjustment for injury severity. These findings were consistent across different oestradiol metrics (peak, area under the curve, and absolute change). Discussion: be an integral component of the early systemic response to polytrauma and are associated with injury severity and adverse outcomes. These findings challenge the concept of oestradiol as a uniformly protective factor and support its role as a marker of post-traumatic stress and systemic dysregulation.