Kate Middleton and Meghan Markle wear shorter dresses during their pregnancies for one reason

By now, we've all become accustomed to royal protocol. Conservative hemlines, traditional cuts and pantyhose are an absolute must for the royals, while nude nails and fresh-faced looks make up a long list of beauty rules.

Queen Elizabeth has set quite the precedent during her 65-year reign as monarch -- and these mandates are not something that the Windsor family takes lightly.

But when it comes to royal pregnancies, it seems that some of these royal rules go out the (palace) window.

You may have noticed that Duchess Kate's pregnancy style quickly evolved to include protocol-pushing short dresses and skirts the second she became pregnant with Prince George. Remember *that* polka dot dress when she visited the Harry Potter set at 6 months pregnant?

Apparently, there's a reason the then mom-to-be showed a little leg.

"Highlighting legs and arms is always a good trick to keep a nice silhouette," explained the founder of one of the duchess' go-to maternity brands Seraphine, Cecile Reinaud, to InStyle.

"[Kate] did [go shorter] for sure. She went shorter, on a couple of occasions well above her knee, which she never does normally," she continued. "And especially in winter, because when she wore opaque black tights, it looks okay. It doesn’t look too much because it’s not bare legs, it’s black opaque tights with a shorter dress."

It's a look that Duchess Meghan has also replicated as she's moved along in her pregnancy. "Because her pregnancy is going to be a winter pregnancy, I think she’s more likely to shorten her hemline," Reinaud said back in November. And since Meghan's known for her fresh approach to royal fashion, we've definitely seen the duchess' maternity style push the boundaries like her sister-in-law.

For more on the Duchess of Sussex's pregnancy, watch the video above!

RELATED: See Meghan's style before she became a royal