Editor's Note: (Caroline Criado Perez is a writer, broadcaster and award-winning feminist activist. The opinions in this article belong to the author.)
(CNN) When was the last time you did something risky? Went skydiving? Played the stock market? How about downloaded an app that claims to be able to tell you when you can safely have unprotected sex?
If you're a woman on social media between the ages of 18 and 40, you've almost certainly seen an advertisement for a controversial contraceptive app called Natural Cycles.
It claims to offer an effective, "natural, hormone-free and non-invasive" alternative to traditional birth control methods. In this age of jade egg cleanses and vaginal steaming, they've got their messaging just right.
In fact, they've won an award for it: in June, business magazine Campaign awarded Natural Cycles its "Pick of the Month" for a social media campaign that resulted in "a staggering 127% increase in app registrations" and "1,000,000 women influenced."
Beyond traditional advertising, Natural Cycles also uses "influencers" -- a new tribe of online celebs who, with their loyal and engaged social media followings that often number into the millions, are catnip for marketers looking for a more "authentic" way of hawking their products.
This authenticity is largely a sham. In the UK, influencers are legally obliged to mark paid-for social media posts as adverts. But, says criminology professor Natasha Tusikov, "there is research showing that people don't understand the difference between Kim Kardashian posting a picture of herself at the beach and Kim Kardashian hawking a certain product for which she is paid." And surely this confusion is part of the point of using them.
We have long known that celebrities wield a powerful influence over consumers. For this reason, their use in marketing products that carry particular risks has long been regulated in the UK.
Under non-broadcast rules, you can't use a "health professional" or a celebrity to sell a medicine. Broadcast rules are more stringent: celebrities can't recommend "a medicinal product or treatment." This disparity, the Advertising Standards Authority press office informed me, "reflects the long-held view that TV is a more impactful medium necessitating tougher standards."
But in the era of social media, does this "long-held view" remain valid?
There is a dearth of solid research on social media advertising, but Facebook made a huge deal about how much more impactful the Natural Cycles campaign on its platform was than on TV. It claimed a "20% incremental reach on top of TV," "47% more efficient reach per target rating point than TV" and a "higher total reach than TV for women aged 25-34. And all for "3.6x lower cost per target rating point than TV."
There's something unseemly about all this. Natural Cycles is not a harmless toy; it's a medical device. Indeed, the company makes the most of being the only medically "certified" contraceptive app. Natural Cycles is able, it seems, to capitalize on the legitimacy of being medically certified without suffering from any of the drawbacks.
Amy Hough, the lead author of a paper about Natural Cycles, told me that one influencer she spoke to found the app time-consuming "and ended up with a coil that she much prefers."
It is unclear if, under the terms of her contract, the influencer would have been allowed to disclose this to her audience: when I contacted Natural Cycles they refused to share any information about what they allow influencers to say.
But negative experience is relevant. Natural Cycles requires a lot of work from its users in order to give accurate readings. You have to take your temperature at the same time (ideally) every morning. You have to input data on when you're having sex and when your period is. For more accurate results, you can input what level of "luteinizing hormone" is in your urine at various times of the month. Your readings may be off if you're ill, if you work shifts, if you're hungover.
This matters, because the more a contraceptive method relies on user input, the less effective it is. This is why condoms are around 82% effective with typical use, while the contraceptive implant is over 99% effective, according to the UK's National Health Service.
But Natural Cycles doesn't have to mention this caveat on their marketing -- and, naturally, they don't.
In the UK, the Advertising Standards Authority (ASA) ruled at the end of August that Natural Cycles was misleading its customers by claiming that the app was as effective as other methods. This is to be welcomed. But it doesn't go nearly far enough in addressing how Natural Cycles markets itself. It can't, because the ASA regulatory powers don't go any further.
This contrasts sharply with financial products, which in the UK and the US are subject to a high level of regulation. And it shows.
"Banking is traditionally not known to use influencer marketing," explains Holly Pavlika, an expert in social media marketing, because the "legal regulations associated with promoting and endorsing investment products can create a more strict environment that takes away from the authenticity and human touch of an influencer's post."
Influencer marketing, says Pavlika, is for "passion products," not for risky ones, and a company advertising a financial product in the UK and the US must be clear and upfront about the risks. In an advert for an investment product, for example, the company would have to state that your capital could be at risk. It must carry the same prominence as the benefits presented in the advert.
This makes sense. Investment products are risky. But if something goes wrong with Natural Cycles, I run the risk of getting pregnant -- and yet no advert I've ever seen for Natural Cycles (and I've seen many) was accompanied by anything along the lines of "your uterus may be at risk of not being empty."
And my uterus not being empty is no small thing.
Numerous studies have claimed to show that men are more risk-taking than women. Men skydive and gamble; women stay home and look after the kids.
But is having kids risk-free? Not according to academic psychologist Cordelia Fine, who in her award-winning book "Testosterone Rex" points out that "being pregnant is about twenty times more likely to result in death [in the US] than is a skydive."
In Australia about half of women who have had more than one child have some degree of pelvic organ prolapse, a condition for which treatment is inadequate. A woman in the UK died after having a mesh inserted to treat her prolapse. Last year it killed a woman in Canada.
There are financial risks, too. In the UK, by the time a child is 20, mothers earn almost a third less per hour than equally qualified fathers, according to researchers.
So why is it that a spare-change investment app must carry a warning while a contraceptive app can ramble on about how great it is to be hormone-free?
The US Food and Drug Administration (FDA) has specified that Natural Cycles adverts be clear about potential risks, for example, by including "a statement that no contraceptive method is 100% effective."
But there's a chance this stipulation may inadvertently mislead women, since it implies that Natural Cycles is of comparable risk to other birth control methods -- something Natural Cycles again makes the most of in its ads, proudly citing "clinical studies" showing that the app is 93% effective, "which is in the same category as other conventional methods."
There is reason to be skeptical about this claim. Birth control methods like the pill or the coil have been tested numerous times, over decades, in independent trials.
By contrast, two of the lead authors of Natural Cycles' 2017 study were the company's founders, and experts say the data (harvested from users' app inputs) is full of holes.
When I asked Natural Cycles if they would make their data available to other researchers so that their claims could be replicated, they told me that they currently "do not have plans" to do so.
The Swedish Medical Products Agency recently investigated Natural Cycles after 37 women fell pregnant at a single hospital while using the app, but ultimately closed the investigation, ruling that the number was in line with the 93% figure.
This is naturally good news for Natural Cycles. But the ruling cannot be a substitute for the proper randomized clinical trials that have been called for by the Family Planning Association and a 2012 Cochrane Review. And it does not, in any case, address any of the issues about the level of informed consent women who are being influenced online are able to give.
It is clear that we need more data on the efficacy of contraceptive apps and on the impact of social media. And we need to update our outdated views on advertising and on risk.
The distinction between broadcast and everything else was made before the advent of the smartphone and social media. It made sense back then. It doesn't today.
This is a world where celebrities have direct contact with their often-impressionable followers and where anyone can upload a video to YouTube, Facebook or Instagram. And unless we have regulation that recognizes this, well, that seems pretty risky to me.