Allemand, 29, was taken to University Hospital after "a serious emergency medical event" on Monday night, ABC said in a statement. The network would not elaborate on what the medical event was.
Allemand's mother and long-term boyfriend, NBA player Ryan Anderson of the New Orleans Pelicans, are both with her. "On behalf of the family, we kindly ask for privacy at this time," ABC said.
A swimsuit model best known for appearing in Maxim, Allemand also competed on the first two seasons of Bachelor Pad.