Queen Elizabeth usually attends the State Opening of Parliament, but she skipped the event on two occasions. The first one was in 1959 and the second time that she skipped it was in 1963.

The reason behind this has just been revealed. In both years, Her Majesty was pregnant with two of her children. In 1959, she was pregnant with Prince Andrew. And in 1963, she was pregnant with Prince Edward.

Decades ago, royal pregnancies were kept as low-key as possible. The changes in the outlook when it came to royal pregnancies only came into effect after the Earl of Wessex was born. As such, the Queen was forced to skip certain occasions until after she has given birth.

In 1948, Buckingham Palace also released a statement saying that the Queen will not be performing her royal duties and she won’t also be making an appearance starting the end of June. The palace didn’t reveal the reason why but months later, it was announced that the monarch gave birth to her eldest child, Prince Charles.

Since the Queen usually goes into hiding while she’s pregnant, there are very few photos of her with her growing baby bump. Photos of her newborn children are not also released until after their christenings.

But decades later, royal pregnancies, announcements, and photos changed with the arrival of Princess Diana. Shortly after she joined the royal family, she became pregnant with Prince William.

The palace announced her pregnancy to the entire world, and she continued her royal duties while sporting her growing baby bump. As such, there are tons of photos of Princess Diana during her two pregnancies.

And after her sons were born, the Prince and Princess of Wales immediately stepped out in public to introduce their children to the public. Princess Diana was also the first member of the royal family to give birth at the hospital and to send her children to public school.

Queen Elizabeth II Prince Philip Prince Andrew and Prince Edward
Pictured: Prince Harry, Prince Andrew, Queen Elizabeth II, Prince Philip and Prince Andrew watch the flypast over The Mall of British and US World War II aircraft from the Buckingham Palace balcony on National Commemoration Day July 10, 2005 in London. Getty Images/Daniel Berehulak