|Source: The British Monarchy; picture: Hugo Burnand|
The Duchess was admitted to the hospital with hyperemesis gravidarum. This is acute morning sickness and requires extra fluids and nutrition.
The official announcement from St. James Palace read:
Their Royal Highnesses The Duke and Duchess of Cambridge are very pleased to announce that The Duchess of Cambridge is expecting a baby.
The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall and Prince Harry and members of both families are delighted with the news.
The Duchess was admitted this afternoon to King Edward VII Hospital in Central London with Hyperemesis Gravidarum. As the pregnancy is in its very early stages, Her Royal Highness is expected to stay in hospital for several days and will require a period of rest thereafter.
Hyperemesis Gravidarum is very acute morning sickness, which requires supplementary hydration and nutrients.Currently only a firstborn boy will receive the title of Prince of Cambridge with the style of Royal Highness. If their child is a girl, she will be styled Lady .. Windsor. Only the oldest son of the oldest son of the Prince of Wales is entitled to the title and style of HRH Prince of the United Kingdom of Great-Britain and Northern Ireland (Styled Prince of Cambridge), however it is likely HM Queen Elizabeth will announce that any child born to the Duke and Duchess of Cambridge wil have the title and style of HRH Prince(ss) of the United Kingdom of Great-Britain and Northern Ireland.
The baby will be third-in-line of succession to the British Throne, preceded only by his or her father and grandfather.