Can your phone prevent pregnancy better than the pill?

As a fertile, sexually active woman who sleeps with men, trying to remain childless is a minefield. It can feel like a full-time job, oscillating between hormonal meltdowns and paranoid suspicions that you could be experiencing one of those pregnancies you don’t know about until you give birth in a cubicle at work.

But, contraception is at a crucial intersection. We know that the pill can have a devastating impact on the mental health of some users, and thanks to increased conversations (and fads) surrounding wellness and natural lifestyles, women, and eager entrepreneurs, are looking for non-hormonal options. As you’d expect – there’s an app for that.

Natural Cycles is trying to bridge the gap between the modern woman’s quest to “go natural” and the unfortunate fact that we’ve become really out of tune with our bodies. Although the year-old app has gained 700,000 users worldwide, it came under fire last week after a spate of pregnancies were linked to its usage. Södersjukhuset hospital in Stockholm logged 37 unwanted pregnancies from Natural Cycles, and reported it to the Swedish Medicines Agency.

The news led to huge criticism online, with many people asserting that trusting an app to ward off pregnancy was “stupid”. One user called the app a “glorified diary,” while another quipped: “What do you call people who use the Natural Cycles app? Parents.”

But Natural Cycles co-founder Dr Raoul Scherwitzl’s confidence in the science has not been knocked by the recent backlash. “No contraception is 100 per cent effective,” he tells Dazed. “It's a truth you cannot get around. The more popular we get, the more happy users we will have, and a small fraction of women will have unplanned pregnancies. This is exactly what is happening in Sweden. We have the highest density of Natural Cycles users here. So, unfortunately, that means that a fraction of them will end up with an unintended pregnancy. We've had large investigations that confirm that there's no reason to believe that there's an issue with the product.” The app was approved and certified by the regulatory body Tuv Sud, the science behind the app does backup Scherwitzl’s point: its 99 per cent effectiveness ranks it more effective than condoms (which have a 98 per cent success rate).

That’s because the science that Natural Cycles uses is nothing new. Scherwitzl started the app with his wife Elina Berglund when she, a fellow scientist, created an algorithm to avoid pregnancy while taking a break from the pill. “The way it works is that a woman measures her temperature in the morning, enters that data into the app and then the app returns a red or green day. On red days you should use protection (we recommend condoms) or abstain from vaginal intercourse, as you are fertile during these days. On Green days you do not need to use protection as you are not fertile, the app considers no risk of pregnancy.” Tracking a rise in temperature is a natural family planning method that has been proven to work for hundreds of years. “What is new is the fact that we have moved the need from the woman, or the couple, to learn about the subject first and then also to analyse the data themselves.”

The couple vouched for its effectiveness after they conducted a study of 4,000 women who found the app to be more effective than the pill. This stat attracts thousands of users a month, mostly women who have had negative experiences with hormonal treatments. Like Silvia Monteiro, a 30-year-old who has been using the app for a couple of months.

“No contraception is 100 per cent effective. It's a truth you cannot get around. The more popular we get, the more happy users we will have, and a small fraction of women will have unplanned pregnancies” – Dr Raoul Scherwitzl, co-founder of Natural Cycles

“I used everything under the sun,” she tells Dazed. “I’ve been on several different pills. I’ve had the hormonal coil and the copper coil. I needed to avoid the fact that there are just too many side effects. What I’ve found using Natural Cycles is that I’ve just got to know my body a bit better – and I’m not very good at maths to do it without the app.”

For the most part, she completely trusts the science behind the app (“any errors or failures are usually because you’re not using it correctly, which is the same for other types of birth control as well”), but she still has some trepidation to use it without protection on all of the green days for the first couple of rounds, just while it gets to know her cycle.

This is something that was echoed by Anita Egueye, 24, who uses Clue, a period tracking app that indicates your least fertile days based on a range of bodily changes from your level of exhaustion to the consistency of your poo. “Periods can change so much, it’d be a bit silly to use it as your only contraception from the beginning. That’s probably why people get pregnant (while using the app) – because if they’ve been using the pill, and stop, the body has to get used to that, and would be a bit messed up.”

This theory that the “transition period” between the pill and the app was responsible for unwanted pregnancies was widely repeated online after the Swedish pregnancy scandal. However, Scherwitzl says that the app can accurately prevent pregnancy from day one. “In the beginning, the app doesn't know as much about the woman so the app will give more red days (infertile periods when you can have unprotected sex). As time goes on, as more and more data is entered, the algorithm gets to know more and more about that particular woman. Then, they are good to go.”

Zoe Cassell, 24, primarily chose Natural Cycles because of the exhausting side effects of hormonal contraception, but for her another key factor was her stable lifestyle and the fact that having a baby wouldn’t “ruin” her life. “My boyfriend and I had been together for two and a half years and living together for six months, in stable jobs,” she explains. “We are both aware that a certain number of women will become pregnant while using Natural Cycles. It does worry me slightly, but women become pregnant when taking the contraceptive pill. I am cautious on the green days either side of predicted red days. We sometimes use condoms on those days, just in case ovulation is late or early.”

So despite Natural Cycles’ confidence in the product, not everyone shares their unwavering faith in the algorithm. After all, there’s still plenty of room for human error – and medical professionals are sceptical about whether we totally trust the stats boasted by Natural Cycles.

“It does worry me slightly, but women become pregnant when taking the contraceptive pill” – Zoe Cassell, a Natural Cycles user

Dr Diana Mansour is the Vice President for Clinical Quality at the Faculty of Sexual and Reproductive Healthcare (FSRH), and also acts as a consultant in gynaecology and reproductive healthcare. Her concern isn’t for the science behind the app, it’s for the impressive results the creators have used to market the products – the trouble is it’s not very impartial to conduct your own study. “Without an independent study, we can’t say for certain how effective (Natural Cycles or its competitors) are.”

“There are hundreds of apps which claim to help users plan or prevent a pregnancy – these come in all manner of forms and some will be more effective than others,” explains Dr Mansour. “Women who wish to use fertility awareness-based contraception are advised to receive guidance from a qualified teacher to learn how to effectively monitor the different indicators. Apps currently do not come with this teaching, leaving room for misunderstanding and inaccurate use.”

It’s understandable for people to be sceptical when it comes to new technology and medicine. Natural methods of family planning traditionally take a great level of personal education in the wonderful world of eggs and sperm, and more importantly, the greatest level of responsibility for knowing your own body. Given that Scherwitzl and Berglund promote the idea that the user does not need to educate themselves about fertility to use their product, they co-sign the erosion of personal responsibility. So of course, the small number of women who fall pregnant will blame the app.

In the end, it all seems to boil down to personal discretion rather than blind faith in any method of contraception. The women we spoke to know the app is a starting point, but that they have to tailor and monitor their own user experience so they feel comfortable. The method behind what social media called “madness” is sound – the science dates back centuries. What’s new is the digitisation of one of our body’s most natural processes. Of course, you can’t hand over the control of your uterus to a piece of software, but it might help.