Objective Determine if concussed females have longer recovery times than males, and if delayed recovery time can be determined by changes in cerebral blood flow.

Design Prospective study.

Setting Tertiary Hospital Concussion Clinic.

Participants Children, 12–16-years, one year, N= 262.

Interventions (or Assessment of Risk Factors) Participants had demographic, injury and clinical data collected, and managed by concussion clinician. A subgroup underwent a standardised ultrasonography protocol evaluating internal carotid (ICBF), and transcranial (TCBF) blood flow to determine CBF. This cohort had end-tidal CO₂, ECG and BP monitoring throughout the examination, and underwent examination in the supine and seated position as well as pre- and post-graded exercise testing. All patients were followed up until recovery complete.

Outcome Measures Injury- recognition, recovery, CBF- post-injury, exercise.

Main Results 262 patients, mean 14.9 years, 46% female, concussed during organised sport. Females were three times more likely to delay seeking medical care following injury and twice as likely to have a slower recovery compared with males. A sub-group of 42 participants, including 18 females, were matched to controls, and underwent ultrasonography to determine CBF post-injury and exercise. An increase in post-injury and exercise CBF was found which diminished over time to recovery. In males a relationship between CBF and recovery found, but not females, due to greater symptom burden and longer recovery times compared with males.

Conclusions Females delay seeking medical care and are twice as likely to have a prolonged recovery following concussion. CBF response to injury measured by ultrasonography may better predict and monitor recovery trajectory.