Oh... no. This very unfortunate bikini design makes it look like you've got your period.

With winter less than six weeks away, now is usually the time of year where our swimwear goes into hibernation, unless we have a tropical holiday planned (we… wish).

But, on the other side of the world, things are just heating up. Summer’s about to begin, which means swimwear and beach essentials are everywhere.

And although swimwear trends are always pushing boundaries – like, do you want a bikinis with buckles? (The answer is probably no) – there’s one Marks & Spencer bikini set that is truly baffling customers, thanks to a very unfortunate pattern.

The £36.50 (AU$66) Printed Lace up Plunge Bikini Set features a design that is supposed to be a sunset, but many believe the bottoms look like... well, a pretty large period stain.

And while we're all for ending the stigma around periods, wearing a bikini that makes it look like you forgot to take your mooncup to the beach is not how we thought it would happen.

The store website says the bottoms will instantly make you feel like grabbing your beach towel and yes, they will, but probably just to wrap it around yourself as you head to the bathroom to sort the mishap out.

It's a bloody (sorry) awkward design flaw, and people of the internet were happy to let M&S know that menstrual chic is not going to happen.

I think the M&S designer was having a bad day, not a look I want to go for this summer ???? pic.twitter.com/afbJYkqXJB

— Bex Renshaw (@bexrenshaw) April 19, 2019

While most of the public believe that this bikini won't be flying off the shelves, the response has not been all negative.

A sole review on the M&S website gives the swimsuit 5 stars, with the reviewer describing it as having a "nice fit" and being "very flattering".

It's possible M&S is hoping to remove the stigma surrounding periods (and if so, all power to it!), but we can't help but think this is probably just a design that wasn't quite thought through.