Traditionally, the due date and gender of a royal baby are shielded from the public until the day they are born.
The same privacy rules apply to sharing ultrasound images, which changed for the very first time when Prince Harry and Meghan broadcast their sonogram with the world via their Netflix docuseries.
In episode four of the six-part chronicle following the Duke and Duchess of Sussex's complex royal journey, an ultrasound scan image captured during Meghan's pregnancy with Prince Archie was shown on screen. Take a look in the clip below...
More images of Meghan's growing baby bump were also featured in the documentary, including a set of romantic photobooth portraits captured shortly after Prince Harry and Meghan discovered they were going to become parents for the first time.
The Duchess reveals they bonded over wanting to be parents and tells Harry, "One of the things we connected on very early is you always wanted to be a dad, and I always wanted to be a mom."
She continued: "We started journaling the minute we found out we were pregnant. It was just 'Dear baby, we're so excited to meet you one day'. And we'd take little snapshots and stick them in the journal."
Prince Harry and Meghan's baby scan marked the first time in royal history that this kind of information had been shared with the public.
The reason why the royal family prefers to keep their baby scans private has never been explicitly revealed by Buckingham Palace, though it does fall in line with the palace's general privacy rules surrounding personal medical information.
An ultrasound scan is, afterall, a look inside the uterus to see if the baby is growing properly or if there are any potential problems with the pregnancy. It only makes sense that the world's most watched family choose to keep this personal piece of medical information to themselves.
Meghan and Harry went on to welcome their firstborn on 6 May 2019, and on 4 June 2021, their second child was born, a daughter called Lilibet.
In another break from royal tradition, Harry and Meghan did not publicly reveal the names of Prince Archie's godparents, however four of the individuals were later reported to be Harry's close friends, Charlie van Straubenzee and the 7th Duke of Westminster, family friend Mark Dyer and the Duke's former nanny, Tiggy Pettifer.
Similarly, Princess Lilibet's godparents are unknown but prior to her baptism, Hollywood mogul Tyler Perry revealed he had been asked to be the tot's godfather in Harry and Meghan's Netflix docuseries, released in December 2022.