Duchess of Cambridge Kate Middleton is expecting her third child with her husband Prince William. Both the Queen and the Middletons are delighted by the news.
The duchess, "as with her previous two pregnancies ... is suffering from hypermesis gravidarum" otherwise known as a severe case of morning sickness. This caused the duchess to decline an appearance at the Hornsey Road Children's Centre on Monday afternoon.
The duke and duchess' other two children, George (4) and Charlotte (2), were equally affecting. The first time the duchess was treated at the hospital in 2012. The second time she was treated at the palace in 2014.
According to BBC, hyperemesis gravidarum "affects about one in every 200 pregnancies and results in severe nausea and vomiting - with one of the main dangers being dehydration."
Due to her condition, the duke and duchess have had to announce their happy news ahead of schedule, and not at a convenient time for their royal duties. While the couple was "poised to take on more royal duties" soon, they now have to make room for the newest member of their family.
Prince George stands to be crowned monarch, so it is unlikely this new prince or princess will sit on the throne. However, the baby will still gain some global interest, considering their grandmother is the late Princess Diana.
Nicholas Witchell, the BBC's royal correspondent, says the news has certainly come at a busy time for the royal family, since "Prince George is due to start at big school."
"Presumably his mother would be keen to take him to that, [but] whether she is going to be well enough to do that remains to be seen," he told BBC News. "It had also been expected that the Duke and Duchess of Cambridge would be taking a foreign trip this autumn. Whether they will be able to do that or whether the duchess will be well enough to do that also remains to be seen."
The third-born child of any royal in the current House of Windsor has yet to become monarch, and the likelihood of that happening is rare. However, it is not impossible. William IV, the third child of George III and Queen Charlotte, ruled from 1830 to 1837.
This will bump Prince Harry, Prince William's younger brother, to sixth in line for the throne.