Kate Middleton faces period of rest alone as Prince William returns to RAF

The Duchess of Cambridge is expected to take time off from her royal duties until Christmas after being discharged from hospital on Thursday.

The Duchess, who spent three nights in the King Edward VII Hospital in London being treated for a severe form of morning sickness, has cancelled two engagements this weekend and is unlikely to be well enough to attend a third next week.

She has been told to rest at Kensington Palace for at least a week, meaning she is unlikely to be seen in public again until the Royal family's Christmas Day church attendance at Sandringham.

The Duchess, 30, smiled broadly as she left hospital at 10.45am holding a bouquet of yellow roses given to her by hospital staff, saying she was feeling "much better, thank you" as she got into a waiting Jaguar with her husband.

A St James's Palace spokesman said: "The Duchess of Cambridge will head to Kensington Palace for a period of rest. Their Royal Highnesses would like to thank the staff at the hospital for the care and treatment the Duchess received."

The Duchess, who missed a planned engagement at a fund-raising day in the City on Wednesday, has already pulled out of attending a ball in aid of Centre-point, the homelessness charity, at the Royal Albert Hall on Saturday night and an appearance at the British Military Tournament at Earl's Court on Sunday, though the Duke of Cambridge plans to attend both events alone.

The couple had also been due to attend the Royal Film Performance of The Hobbit in Leicester Square next Wednesday, but aides said the Duchess's presence was "doubtful", adding that she would be "governed by medical advice".

Maternity experts suggest she will need to take at least two weeks off work. Her condition also means she and the Duke will be separated for days at a time over the coming weeks, with the Duke due back on shift with his Search and Rescue squadron at RAF Valley, Anglesey.

The Duke cannot afford to take any more time off, as he would be in danger of dropping below his minimum required flying hours for the year, having already taken time off for the Olympics and the couple's tour of the Far East.

The Duchess will remain in London, within easy reach of her doctors, until she is fully recovered, and may also spend time with her parents in Berkshire, but is unlikely to risk returning to the couple's isolated home in Anglesey until she is completely over her sickness, which could take weeks or even months.

The Duchess's condition, hyperemesis gravidarum, usually clears up after the first trimester, but can carry on until full term and sometimes needs further spells in hospital. She has not yet reached the 12-week stage of her pregnancy, though St James's Palace has not disclosed how far through her pregnancy she is.

Caitlin Dean, a trustee of the charity Pregnancy Sickness Support, who suffered from the same condition, said: "She will need people to look after her, literally bring food to her and quickly. If she wants a piece of toast or an apple, it needs to come straight away before a bout of nausea sets in. Hyperemesis can be quite cyclical. She will be feeling quite good now because she's hydrated, but she needs to keep taking fluids or that cycle can start again."

Bookies have now taken tens of thousands of bets on the royal baby's sex, name, weight, hair colour and the possibility of twins or triplets. Victoria is now the clear favourite, at 9-1 with Coral, followed by Diana and George at 12-1 and John and Elizabeth at 16-1.