Brooke was riding Orchestrated for her mother, Lady Susan Brooke, when falling at the third fence in the Pontispool Equine Sports Centre Handicap Chase on April 8.
Racing was delayed by more than hour as she was treated on track, before being transferred into an air ambulance.
A statement issued by the IJF on Friday said Brooke was in a “critical, but stable condition” in intensive care at Southmead Hospital in Bristol, and had been placed in an induced coma due to “various complications” during the week.
However, a further statement released on Monday confirmed she had died.
The statement read: “It is with deep sadness that we have to share the tragic news that Lorna Brooke passed away yesterday.
“Her family thank everyone for their kindness in the last few weeks, particularly the staff at Southmead Hospital who were so professional.”