What a mystery.

People are just realising they've never seen evidence of Queen Elizabeth's pregnancies - even though when she was expecting, Prince Andrew, the Duke of York, she became the first reigning monarch to give birth in 103 years. Both King Charles III, and Anne, the Princess Royal, were born before Elizabeth became Queen. Prince Edward was born 12 years into the Queen's reign, in 1964. Despite all of this royal fans have noticed that she's only been pictured with a baby bump once and even then it wasn't a clear or close up picture. It was 1960 and Her Majesty was expecting the birth of her son Prince Andrew in a month. [caption id="attachment_359441" align="alignnone" width="2048"] Queen Elizabeth II and Prince Charles walk through Liverpool Street Station in London with their dogs, having returned by train from Sandringham after the Christmas holidays, 18th January 1960. The Queen was expecting the birth of her son Prince Andrew in one month's time. (Photo by Derek Berwin/Fox Photos/Getty Images)[/caption] This was because it was seen as taboo at the time for pregnant women to be seen in public. According to Harpers Bazaar, the Queen wasn't even allowed to announce that she was expecting. The public was simply told she would put a hold on her royal duties. A statement issued in 1948 by Buckingham Palace read: "Her Royal Highness Princess Elizabeth will undertake no public engagements after the end of June." Unlike pictures of Princess Diana and Kate Middleton, the new Princess of Wales, no public photos of the Queen on the hospital steps were taken, as is tradition today when a royal baby is born. To be fair, that is because Prince William was the first heir to be born in a hospital. The day after he was born, Princess Diana and Prince Charles were pictured with their son as they exited St Mary's Hospital in Paddington. Kate Middleton and Prince William posed similarly after Prince George's birth in 2013. The Queen reportedly hated the word "pregnant" and banned it being used around her as she found it "vulgar". She insisted that people referred to pregnant women as being "in the family way", which is an old fashioned phrase that nobody uses anymore.