But, if her previous two births are anything to go by, the couple could welcome their third child into the world on April 27 or 27.
When she was pregnant with Prince George, Kate attended her final engagement on 15 June, before taking maternity leave. George was born just 36 days later on July 22, 2013.
In 2015, when she was expecting Charlotte, Kate enjoyed 35 days of maternity leave, before she gave birth on May 2.
This time around, Kate undertook her final engagement on March 22 before taking maternity leave.
So, given that pattern, the royal tot could be born on April 26 or 27.
Mark the dates in your calendar now!