For one thing, being a royal means following lots and lots of guidelines and traditions.

What’s more, there are even a few additional royal fashion rules when it comes to pregnancy.

Here are some of the royal fashion rules that women are supposed to follow even when pregnant.

Princess Diana pregnant

Princess Diana began the tradition in the ’80s when she showed off the newborn Prince William to photographers.

Catherine wore three different Jenny Packham dresses for her post-birth photo sessions.

Both Meghan Markle and Princess Diana were also dressed up after their respective births.

Prince William and Princess Catherine with baby

Most doctors recommend wearing comfortable shoes with an open-toe design to allow the feet to breathe.

For the royals, however, the relief of a pair of breathable sandals is off the table.

You will rarely see a royal wearing open-toed shoes in public even while they’re pregnant.

Princess Diana pregnant in green dress

According toHarper’s Bazaar, the royals are strongly discouraged from donning open-toed shoes.

“Open-toed shoes are considered informal footwear and inappropriate for formal occasions,” etiquette expert William Hanson said.

While they may be “inappropriate,” they are not formally banned.

Kate Middleton in a black polo shirt

Hey, sometimes you’ve just got to let your tootsies breathe.

Well, not for the royals.

Apparently, royal women should not wear tracksuits, sweatpants, or even leggings while pregnant.

Meghan Markle pregnant in a green dress

Of course, there are a few very specific exceptions to the rule.

Well, it turns out royal women have to be very, very careful about showing cleavage.

For instance, Meghan Markle and Princess Catherine were often spotted wearing high-necked tops and modest coats.

Kate Middleton in a yellow dress

Understandably, plenty of pregnant women would hate the thought of keeping their coats on inside.

As it turns out, even pregnant royals are supposed to follow this rule.

And when royals start to feel a little too hot under those maternity coats?

Prince Harry and Meghan Markle

“Kate leans into this stuff much more than Meghan did.”

Nevertheless, Catherine was spotted wearing pantyhose while pregnant in 2018 numerous times.

In 2019, Meghan, while heavily pregnant, broke the rule.

Kate Middleton pregnant in tights

“Highlighting legs and arms is always a good trick to keep a nice silhouette,” said Reinaud.

And especially in winter, because when she wore opaque black tights, it looks okay."

Reinaud went on to predict that Meghan Markle would also opt for shorter hemlines.

Meghan Markle in a burgundy dress while pregnant

Meghan Markle was spotted wearing cute, midriff-baring crop tops before she joined the royal family.

In fact, you will rarely see a royal wearing flats at formal events.

Apparently, this rule continues to apply throughout all nine months of a royal’s pregnancy.

Prince Harry and Meghan Markle walking

In June 1984, a pregnant Diana wore a pair of pink heels to watch the polo.

The heels don’t go anywhere when the baby arrives.

However, royal women don’t have the option to simply throw on an easy, flattering all-black outfit.

Meghan Markle and Prince Harry

This rule even applies to pregnant royals who may wish to keep things simple with a black ensemble.

Pregnant Meghan Markle wearing all black