If Kate remains at her London home at Kensington Palace, the already confirmed venue of Lindo Wing at St. Mary's hospital in the UK capital will remain unchanged.
However, if her pregnancy drags on she may decide to visit her parents in Bucklebury, Berkshire, or may even choose to stay at Anmer Hall, the royal couple's newly-refurbished country home in Norfolk.
As a result, two local hospitals - the Royal Berkshire in Reading and the Queen Elizabeth Hospital in King's Lynn in Norfolk - have been put on standby, with the Duchess of Cambridge's obstetricians advised that they could be summoned to either location, according to 'The Daily Telegraph'.
The Duke of Cambridge and Prince Harry were both born at St Mary's in London, as was Prince George most recently.
His grandfather Prince Charles and his brothers, Prince Edward and Prince Andrew, were delivered at Buckingham Palace, while Charles' sister Princess Anne was born at Clarence House in London.
The Queen was born in 1926 at her grandparents' London home in Mayfair.
If the baby is born tomorrow, he or she will share its birthday with great-grandmother Queen Elizabeth II, who will be 89, while April 29 will be his or her parents' fourth wedding anniversary.
There is also the very remote possibility that if the baby is overdue it could be born on May 7, the day of the UK General Election.
The birth has triggered a betting frenzy among the British public, who predict a blonde baby girl named Princess Alice based on the current odds.
