Title: Progesterone Treatment of Blunt Traumatic Brain Injury Principal Investigator(s): Arthur Kellermann, M.D., M.P.H. Institution: Emory University Biostatistician: Vicki Hertzberg, Ph.D. Institution: Emory University Project phase or primary methodology: Phase II pilot, double blind, 4:1 randomized controlled, clinical trial Target disease: Blunt traumatic brain injury Intervention: Intravenous progesterone infused over three days Number of patients to be enrolled: 100 Number of clinical centers: One (Grady Memorial Hospital) Primary Hypothesis: Dose: Intravenous infusion of progesterone at a dose of 0.5 mg/kg/hr produces a steady state of 450 +/- 100 nmol/L in male and female subjects.