From mysterious blue liquid on sanitary pads to euphemistic images of women roller-skating in white jeans, advertising around feminine products has long been restricted by a taboo around the products that resulted in being alluded to rather than shown in any realistic form.

But advertising has increasingly challenged tradition: Hello Flo has used comedic fun around menstruation, while PSAs protest taxes on feminine products (like a recent film starring Amber Rose with a jewel-encrusted tampon holder.) Now, Libresse, a European brand owned by Essity (the healthcare arm of Scandinavia's SCA spun off earlier this year), has broken perhaps the biggest taboo, by showing what periods really look like.

The advertiser was the first to show actual blood in a U.K. ad for feminine products last year, although that spot depicted women bleeding in sport. Now it has gone much further with a groundbreaking film that shows, for the first time, blood that's clearly menstrual. Among its many images are blood running down a woman's leg in the shower, and red blood being poured onto a sanitary towel.

These are not the only firsts for the ad. It also shows women experiencing period pain, and suggests a woman is having sex during her period. Meanwhile, other images set out to portray a world where periods are not hush-hush: a woman's out-of-office reply that states she's working at home because she has a heavy period; a girl goes to a costume party dressed as a sanitary pad; and a man happily buys a pack of sanitary pads in a store.

The film ends with a girl going to the bathroom and removing a pad from her underwear. At this point, the screen pixelates as we are told that, according to "assorted TV broadcast authorities worldwide" in 2017, "the sight of period blood is unacceptable." The ad ends with the message: "Periods are normal. Showing them should be too."

Copywriter Nicholas Hulley and Art Director Nadja Lossgott, creative partners at AMV BBDO in London, worked on the brief. Rather than deliberately setting out to shock or be provocative, Lossgott says, "we wanted to create a world where periods didn't feel shocking or gross." She adds that the aim was to "treat periods like the most normal thing in the world, where boys pass pads to girls, and women ask for pads across a dinner party table, and you can go to a fancy dress party dressed as a bloody sanitary pad, and period pain is recognized rather than suffered in silence just to spare the blushes of men."

Getting it past regulators wasn't easy: both describe it as "by far the most difficult job any of us have ever worked on."

"Every setback shocked and surprised us and it proves just how deep that shame runs," Lossgott says. "We had to fight tooth and nail with lots of different bodies over many months, scene by scene."

Two versions of the ad were finally approved, a longer, more graphic version to run online and in Scandinavia, and a 20-second cut-down for the U.K. (where Libresse is known as Bodyform). Martina Poulopati, global brand communication manager, GHC Feminine Care, Essity, says: " The U.K. was subject to more scrutiny than the Scandinavian countries. But the internet is global. We do hope that the incredibly positive reaction we have had will convince authorities that their fear of these films 'causing widespread offense' is unfounded."

Daniel Wolfe, who directed the film via Somesuch, is best known for his work on brands such as Honda, Hennessy and Powerade, as well as music videos. The team chose a male director for an ad that speaks so much to a female audience because "Daniel is incredible at drawing realistic performances out of non-actors, which adds so much credibility to the film," says Hulley. "His visual style adds such beauty to anything he does, and his intelligence and empathy meant he could help us make a film that is a love letter to both women and periods."

Wolfe himself admits he was "surprised" to be sent the project. "I did a great deal of research," he says. "Starting with lots and lots of reading. The Little Red Book. Forums. And then lots of conversations." He was particularly inspired, he says, by a poem he read by Dominique Christina, as well as by a social media post on the topic: "Can't wait for the day when women no longer pass tampons to a friend like they are a Class A drug."

Wolfe street-cast many of the women in the commercial, aiming to avoid "unrealistic stereotypes -- Lara Croft types, kicking down doors on their period, empowered ideals."

In addition he "wanted to show blood in a way which wasn't shocking nor fetishized. Sometimes very simply and truthfully, like the shot of the blood running down the woman's leg, sometimes more emotively, sometimes comedically like the sanitary pad fancy dress scene."

For the abstract imagery of blood that appears in the film, Wolfe turned to artist Chris Parks, someone he'd worked with before on videos for Paolo Nuttini and Hennessey. "I asked him if he could work with only red and try and create some images for the narrative."

The aim above all was to create "a new normal," says Wolfe. "So the joke 'I had my first period and it wasn't blue' becomes a relic, a comedic reminder of an antiquated media stance."