The duchess of Cambridge is now on London St. Mary's Hospital in work with a third child for her and Prince William.
Here are some highlights of the king's couples and their children's lives:
* September 2001: Prince William and Kate Middleton meet at St. Andrews University in Scotland, where they both study art history.
* Jul 2003: The couple has reportedly become a couple after sharing a house with two friends. In March they are seen on a skiing holiday in Switzerland.
* November 16, 2010: William and Kate's engagement is announced. The Prince proposed Kate during a private holiday to Kenya the previous month.
* April 29, 2011: The couple will attend a sumptuous ceremony in London's Westminster Abbey. William is the Duke of Cambridge by his grandmother, Queen Elizabeth II, and Kate becomes the Duchess of Cambridge.
* December 3, 2012: The castle announces that Kate is pregnant and treated at the hospital for acute morning deficiency. The castle later announces that the child will be due in July.
* June 19, 2013: It is confirmed that Kate plans to feed on the private Lindo wing on St. Mary's Hospital in Paddington, central London, where Princess Diana gave birth to William and Prince Harry.
* July 22, 2013: Kate feeds a baby boy weighing 8 pounds, 6 ounces (3.8 kg), with William by her side.
* July 24, 2013: Royal officials say the new prince, third in line with the throne, has been named George Alexander Louis
* September 8, 2014: Kensington Palace announces Duchess is pregnant with the couple's second child.
* May 2, 2015: Kate gives birth to a daughter weighing 8 pounds, 3 ounces (3.7 pounds).
* May 4, 2015: The castle says the new princess is named Charlotte Elizabeth Diana.
* 4 September 2017: The castle announces Kate pregnant with the third child of the couple.
* September 7, 2017: Prince George starts school at Thomas Battersea, a private school not far from the family home at Kensington Palace. His father releases him on the first day; Kate is too sick with morning sickness to join them.
* March 22, 2018: Kate completes her final royal engagement before going on maternity leave.
* April 23, 2018: The castle says that Kate is admitted to St. Maria Hospital in the early stages of labor.