Kim Kardashian reportedly feared she was having a miscarriage when she was taken ill on board a plane.

The reality star, who is expecting her first child with rapper boyfriend Kanye West, was rushed to hospital after landing in Los Angeles on a flight from from Paris, according to reports.

"Kim started feeling ill on the plane and called friends as soon as she landed," a source told the New York Post.

"She was rushed to her doctor in tears. She thought she was having a miscarriage."

She was discharged within hours but doctors warned her to steer clear of the gym until after the baby is born. Her rigorous workouts are apparently at the root of her health issues.

The source continued: "Kim's not respecting her pregnancy. She's running around, working out seven days a week.

"She's working with two different trainers to control her weight, including a pregnancy trainer.

"She is having a very rough pregnancy and doctors have ordered her to slow down."

Kardashain has previously spoken out about her fears that she would pile on the pounds during her pregnancy.

She told Cosmopolitan magazine she would stick with the gym.