Some have suggested that the Duchess may be due earlier than the July 13 date announced by Buckingham Palace but have kept the true date a secret, much like Princess Diana.
The Palace said she woud be having the baby in the Lindo Wing at St Mary's, Paddington, where Diana gave birth to both William and Harry.
Princess Diana had fooled the press by telling them her first baby was due on her birthday, July 1. William arrived 10 days earlier, on June 21.
The duchess declined to attend the wedding of Melissa Percy and Tom van Straubenzee in Northumberland at the weekend, in case she went into early labour.
The date means she and the Duke could become parents shortly after the Duke's own birthday, which falls in June, or at around the time of the Queen's official birthday, also in June.
St James’s Palace has also moved to end speculation over the gender of the baby by insisting the Duke and Duchess do not know the sex of their baby and have chosen not to be told until it is born.
As details about the arrangements for the birth were released to the media, aides confirmed that Marcus Setchell, the Queen’s former gynaecologist, will deliver the baby, aided by the Queen’s current gynaecologist Alan Farthing, the former fiance of the murdered BBC presenter Jill Dando.
Asked whether the Duchess had opted for an elective Caesarian birth, an option which has led to some mothers being dubbed “too posh to push”, palace sources said she intended to give birth naturally.