The Dutch model is understood to have fractured her skull and and a number of her vertebrae in a surfing accident last week, leaving her at risk of paralysis.
The 33-year-old was rushed to Rizzoli hospital on the island of Ischia before being transferred to a specialist unit in Naples.
The London-based model, who gave birth to a son, Alexander, in July, was riding a jetsurf – a motorized surfboard – when she fell into the water and hit her head.
Italian newspaper La Repubblica has reported that she has now come out of her coma and was showing improvement.
A spokesperson for Next Models, which represents Yfke in the UK, told The Independent: "We are shocked to hear about this terrible accident. Our thoughts are with Yfke and her family at this time and we are praying for her speedy recovery."
As well modelling for Victoria’s Secret, Yfke has also worked for Calvin Klein, Ralph Lauren, Marc Jacobs, Valentino and Chanel.
She also runs her own charity, Yfke 4 Kids, which supports children affected by Aids.