Simpson, who announced that she was pregnant in October, is thought to be at an unidentified hospital in Los Angeles.
Simpson's mother Tina and her sister Ashlee Simpson have arrived at the institution with her, TMZ reports.
The parents of Simpson's fiancé Eric Johnson are also thought to be in attendance.
Speaking on Ryan Seacrest's KIIS-FM show, TMZ's Harvey Levin said: "Her whole family is at the hospital right now."
Simpson, who has joked that she dreamt of giving birth in a leopard print kaftan, was forced to deny rumors that she had given birth last month.