The 27-year-old elite equestrian fell from her horse, named Radio City, in the Gambler's Choice class – a high-speed show jumping competition – when her saddle unexpectedly slipped.
"The Mayor is very concerned, as any father would be," Mayor Bloomberg's spokesman, Stu Loeser, told PEOPLE Sunday.
"She was still for a few moments and then got up with some help and walked out of the show ring on her own," says a horse show spectator who witnessed the accident. "Tough kid."
Georgina "was unconscious immediately following the fall and was also diagnosed with a fracture to her spine," said tournament spokesman Kenneth Kraus in a statement. "The complete medical report ... will become more clear following an in-depth examination on Monday."
This isn't the first time the show jumper has suffered a serious injury: According to the New York Daily News, she has previously broken her back, her collarbone, wrists, an ankle, and suffered several concussions. Still, falls in the sport are not uncommon: Many equestrians will cite the phrase, "you're not a real rider until you fall 100 times."
The equestrian was featured in the 2003 HBO documentary Born Rich and regularly competes in the highest level show jumping competitions.