Congratulations pour in for William and Kate's pregnancy

LONDON: Messages of congratulations poured in from around the world on Tuesday on news that Prince William's wife Kate is pregnant, as she spent a second day in hospital suffering from acute morning sickness.

The announcement on Monday that the Duke and Duchess of Cambridge, both 30, are expecting their first child ended feverish speculation about a new royal heir that began immediately after their lavish wedding in April 2011.

The child, to be born next summer, will be third in line to the throne regardless of whether it is a girl or a boy, after a historic agreement among Commonwealth countries last year to end the practice of male primogeniture.

St James' Palace said Kate was still at the "very early stages" of pregnancy -- she is believed to be less than 12 weeks -- but it is thought the news was released because her admission to hospital would have made her condition public.

Kate has hyperemesis gravidarum, a very acute form of morning sickness which affects 3.5 in every 1,000 pregnant women.

Although it is not dangerous for the baby, it can be highly unpleasant for the mother as it causes severe vomiting and carries a danger of dehydration and nutritional deficiencies.

William, the second in line to the throne after his father Prince Charles, was at his wife's bedside at the private King Edward VII hospital in central London on Monday before leaving at 8.20pm.

He left without a comment or even a smile for the banks of waiting cameras, although his wife is expected to remain in hospital for several days.

There was reportedly a rush to inform members of the royal family of the news before the public announcement, which came just after 4pm (1600 GMT) on Monday.

Queen Elizabeth II, her husband Prince Philip, Prince Charles -- for whom this is his first grandchild -- and his wife Camilla were said by the palace to be "delighted with the news", as were Kate's parents, Carole and Michael Middleton.

William's brother Prince Harry, 28, who will be bumped down a place in the line of succession by the new arrival, was reportedly informed by email in Afghanistan, where he is deployed as an Apache helicopter pilot.

The palace said the couple only "recently" became aware that Kate was pregnant although there has been speculation for months, fuelled by images of the duchess sipping water instead of wine at official dinners.

She showed no sign of being ill at a public engagement on Friday, however, when she showed off her hockey skills at her old primary school in high-heeled boots and an Alexander McQueen tartan coat.

All her public engagements for the coming weeks have been cancelled.