The model-turned-reality TV star, who previously dated Playboy boss Hugh Hefner, is due to give birth to her first child with party promoter boyfriend Pasquale Rotella early next year (13), but she has fallen ill in the late stages of her pregnancy.
Madison took to her Twitter.com page to inform fans she was in hospital to treat a severe bout of morning sickness, and she also uploaded a photo showing her hooked up to an intravenous (IV) drip.
In a series of posts, she writes, ""Almost 7 months and morning sickness took hold! Glad to be otherwise ok, tho (though). Thank you for all the get well wishes! Keeping me entertained - forgot to bring a book with me.""
Meanwhile, the British royal and her husband Prince William went public with their baby news on Monday after Catherine was admitted to a medical facility to treat hyperemesis gravidarum, an acute bout of morning sickness.