Prince Philip ended up taking on some of his wife's duties when she had to rest, prompting speculation about why the monarch didn't have her usual stamina, but there was no rampant media reporting or any official confirmation that a royal baby was on the way.
"It's interesting how during when Princess Elizabeth, and later Queen Elizabeth, was expecting children, how much easier it was to keep news like this quiet," says Carolyn Harris, a Toronto-based royal expert and blogger.
There was nothing quiet, however, about the news Monday as word spread that Prince William and Kate, the Duchess of Cambridge, are expecting their first child.
That rapid dissemination of the latest news from the House of Windsor reflects just how much has changed for an expectant royal in three short generations. In a world of instant internet headlines, Twitter trends and paparazzi hungrier than ever, secrets are even harder to keep.
The announcement came after Kate was admitted to an exclusive central London hospital with acute morning sickness, but weeks before she and William had intended to make their happy news public.
"It's rather unfortunate that the news should break following some sort of account of an illness related to pregnancy. That's kind of hard luck," says Ninian Mellamphy, professor emeritus at Western University in London, Ont., and a longtime royal watcher.
"They're going to have a life that will have very little privacy."
William and Kate will have to be "mature and intelligent," he suggests, and understand the perils of living under the scrutiny of a press that has been less than scrupulous at times.
All of which may shed light on why the announcement came out as it did.
Controlling the message
"I think they wanted to control the situation a bit more just because of the lack of privacy now," says Alanna Glicksman, a Toronto-based public relations consultant and entertainment blogger.
"Anyone from the hospital could have sold the story or leaked it. So at least this way, they were able to control how the message went out and they could make the statement first, before everyone else began to speculate."
Not that there hasn't already been rampant speculation about a pregnancy.
"Everyone's been expecting it for ages," Glicksman says of the news. "The magazine covers have featured it every week, but now they're finally right."
Still, the attention on Kate and her pregnancy will be unprecedented, fuelled in part by the way the communication world has changed.
"With the rise of social media, news regarding royalty spreads faster than it has ever spread before," says Harris, a lecturer in history at the University of Toronto's school of continuing studies.
The next royal baby will be the most anticipated since William's birth in 1982. But Kate's experience is unlikely to mirror that of William's mother, Diana.
"With Diana, the royal pregnancy came very soon after her marriage to Prince Charles," says Harris.
"Diana did her first royal tour of Wales as Princess of Wales and was experiencing morning sickness on that tour. So in a sense she was establishing herself as a member of the Royal Family at the same time … whereas for the Duchess of Cambridge, she's been able to establish herself as a member of the Royal Family before this announcement."
Diana knew, however, that the eyes of the world were on her.
"With Diana, I think her most famous quote was 'The whole world is watching my stomach,'" says Glicksman.
"Everyone wanted to see the heir to the throne and she was under immense pressure."
Diana complained of morning sickness, and was likely suffering from bulimia, but she went out and about on royal duties until near the end of her pregnancy.
Glicksman's not so sure that will happen with Kate.
Long lenses everywhere
"Given how Kate's first trimester is going, I don't think we can say if she'll be able to carry on her royal duties as fully functional as Diana was able to.
"But based on how she's acted in the public up until now, it's safe to assume she does want to be there for the people and continue with her charity work and supporting all the different organizations she works with."
But wherever Kate goes, she can be assured the media will be there — as she found out to great chagrin this fall after photographers with long lenses found her topless on a terrace in the south of France.
And, predicts Glicksman, that constant presence will spawn a particular response from the House of Windsor over the next few months.
"We already know that the paparazzi is very, very vigilant in tracking Kate as evidenced by the photos a couple of months ago. So I think William and the entire Royal Family are going to be very protective over Kate at this time just because they know the attention that's on her and they want to ensure her pregnancy is as safe as possible."
Glicksman says that the decision of William and Kate to make the news public themselves, and by "being so transparent with the public, it sets a good precedent for how they're going to be with the rest of their lives."
The intense interest on the next member of the Royal Family has only begun, and the life the child leads will be scrutinized minutely.
"It will be interesting to see what sorts of decisions the Duke and Duchess of Cambridge make as parents," says Harris.
How many nannies?
"Princess Diana was a very hands-on parent, but her children were still sent to boarding schools, there were nannies employed. So it will be interesting to see what the Duke and Duchess of Cambridge decide to do, how much they will be involved versus the involvement of nannies. They already travel with a much smaller household than other members of the Royal Family have in the past."
Often, says Harris, the arrival of royal children becomes the impetus for change.
Long before Monday's announcement, the chance William and Kate would have a child prompted ongoing efforts to change the rules for succession, giving a first-born daughter equal right with a son to succeed to the throne.
The arrival of William's father, Charles, in 1948 marked another first.
"Prince Charles was the first direct heir to the throne in centuries who did not have a government minister present at his birth," says Harris.
"This was seen as being outdated just as male preference primogeniture is being seen as outdated today, so royal births often spur various reforms within the royal household."
And the child born to William and Kate could prompt other changes that will prove historic in generations to come.