Natural Cycles. (Source: Official Twitter Page of Natural Cycles) 

It’s Tough Being the First Birth Control App

(Bloomberg Businessweek) -- Late one evening last February, Raoul Scherwitzl posted a tweet that, even in this age of oversharing, might have seemed a little too personal: He and his wife, Elina Berglund, would stop trying to avoid pregnancy and begin trying to have a baby. “As of now, the founders of Natural Cycles are switching from Prevent to Plan,” he wrote from Stockholm. “May the odds be in our favor.”

Natural Cycles is a fertility-tracking app the couple had built five years earlier. It’s also the first, and still the only, mobile application cleared for marketing as a certified contraceptive in Europe. In August of last year, it earned a similar distinction from the U.S. Food and Drug Administration, which put a cluster of smartphone-tailored code and pixels in the same regulatory class as condoms. For Berglund and Scherwitzl, announcing their intention to use Natural Cycles to help them procreate felt like a way to hold their technology to account in real time. The method worked: Within a few months, the couple had conceived their second child, who’s due in a few weeks.

The wide availability of the hormonal birth control pill beginning in the 1960s granted women new autonomy and revolutionized their societal and economic roles. But for the subset who must or wish to abstain from hormonal contraception and its accompanying side effects, Natural Cycles provides a powerful alternative. For $99 per year, the app applies a clinically proven algorithm to predict the roughly one week per month during which a woman is fertile. If your goal is to prevent pregnancy—as it is for most Natural Cycles users—the app will show fertile days as red, for when abstinence or condom use is a must, and green days for when they’re not. (Shades of red appear if your aim is conception, with peak fertility showing up as the darkest.)

It’s Tough Being the First Birth Control App

With $38 million in funding, Natural Cycles has outraised many of its women-focused tech peers. It’s still a bit player in terms of active users, though, counting only a few hundred thousand, primarily in the U.K., U.S., and Sweden. While there’s no standard definition for “active user,” and thus no accurate way to compare, free fertility apps tend to boast many times more. Berglund and Scherwitzl—both of whom have doctorates in physics, she with experience at the European Organization for Nuclear Research, better known as CERN—say that’s due to a conscious choice: Requiring users to pay to access any of the app’s features helps ensure they’ll remain committed to inputting data, which is crucial for the technology to work.

Natural Cycles has also worked from Day 1 to build a body of research attesting to the app’s effectiveness. “We’re scientists,” Berglund says. “That’s what we do.” Berglund and Scherwitzl were aware their meticulousness would hamper their growth, but they also view it as the basis for the unique regulatory distinction that’s now their main competitive advantage. There are plenty of fertility and period-tracking apps on the market, after all, but only one that’s allowed to say it will keep you from getting pregnant.

What they didn’t expect is that despite all the work they put into trying to follow the rules, they would still be vulnerable to criticism—in particular to a public-relations crisis that erupted last year after a number of Swedish users became pregnant unintentionally. Detractors questioned the integrity of Natural Cycles’ research and rejected the app’s designation as a contraceptive. “There are so many women who use the other apps as birth control, and they aren’t scientifically backed, and we are the ones that are getting criticism,” Berglund says. “I don’t regret taking this path. But in the end, if this is what’s going to make us fail and someone else succeed, I think the people criticizing us will not have done women a favor. They’ll have done women a disservice.”

There are various physical clues that a woman can use to try to identify her fertile window: the days around when her ovaries release an egg, and the only time during which she can conceive. She can monitor the consistency of her cervical mucus to gauge the level of a hormone that triggers ovulation, or pee on sticks, yet even these tests can be subject to interpretation, in addition to being complicated, costly, and invasive. Another way is to detect the ever-so-slight rise in body temperature that occurs when a part of the ovaries called the corpus luteum secretes the hormone progesterone. But that temperature rise comes only after ovulation. By that time, unwanted conception may already have occurred—sperm can live inside a woman’s body and fertilize the egg her ovaries have just released for as many as five days—or, if she’s trying to conceive, she might have mostly missed her window.

Berglund won’t divulge many details about Natural Cycles’ technology, lest competitors seek to copy it. But she does say it reliably predicts ovulation by taking into account a user’s menstruation dates, fluctuations in her body temperature, and data on the cycles of hundreds of thousands of women. It also adapts to each user: The app will err on the side of caution by showing additional red days when it doesn’t have enough information. The more data a user inputs, the more precise its red day-green day predictions become.

Clinical studies show Natural Cycles is 93 percent effective at preventing pregnancy with typical use, meaning that after a year, seven women out of 100 users will become pregnant. (With perfect use, Natural Cycles is 99 percent effective, according to its research.) That puts it about on par with hormonal birth control pills (91 percent) and beats condoms (82 percent) and the rhythm method (76 percent). But it’s less effective than long-acting reversible contraceptives such as intrauterine devices (almost 100 percent). Even though Natural Cycles wasn’t developed with proponents of so-called natural family planning methods such as the Catholic Church in mind, it’s won praise from those quarters because it isn’t “artificial” birth control that divorces sex from procreation.

It’s Tough Being the First Birth Control App

Berglund, now 35, has a round face framed by thick blond hair that falls right below her shoulders. Growing up, she says, she buried herself in her studies, compelled by an inner drive to be the best. “I was interested in physics from a young age: black holes, the Big Bang, stars, planets,” she says. “I wanted to understand the universe.” She met Scherwitzl, a lanky 32-year-old Austrian with a boyish grin and a mop of dark hair, in 2006, while they were studying abroad at the University of California at Santa Barbara. “I thought the woman who got his smile would be very lucky,” she says. The more the pair got to know each other, “the more clear it became that we could spend infinite amounts of time together without getting annoyed.”

The couple eventually settled in Geneva and pursued doctorates, she in particle physics and he in condensed-matter physics. In 2012, Berglund was working at CERN when her team confirmed the existence of the Higgs boson, a subatomic particle that gives mass to all matter in the universe. “It was the most exciting day of my life,” Berglund says.

The scientists who theorized it would go on to win a Nobel Prize, but the discovery left her at a loss for what to do next. One thing she did know: She and Scherwitzl wanted to start a family in the next couple of years. And in the interim, she wanted to give her body a break from the contraceptives she’d long used. Berglund had had a hormonal implant in her arm for a decade and tolerated it well, but the pill had made her moody as a teenager. Hormonal contraception is generally considered safe (and is correlated with some health benefits, such as a lower risk of ovarian cancer), but some respected studies have shown correlations between its use and slightly higher rates of breast cancer and depression. Also, hormonal contraceptives prevent women from ovulating, and it can take time for ovulation to resume normally after stopping use. “I wanted to get back to my default state,” she says. “I didn’t want hormones to have any impact on me before trying to get pregnant.”

Berglund wasn’t satisfied with the period-tracking apps she’d encountered, none of which could act as effective contraception. So she began researching the correlation between temperature fluctuations and ovulation and wrote a sequence of formulas using a data analysis framework that CERN developed called Root. She plugged in her temperatures to determine her daily fertility status, then did so for friends and colleagues, too. Scherwitzl had long harbored dreams of becoming an entrepreneur, and he began to envision how Berglund’s program could be turned into a marketable product. The couple moved to Zurich so he could support them by working as a management consultant for IBM. Over the next year, Berglund stayed glued to her computer, perfecting her formulas and learning how to develop a website and app. (“Google: How do I make the background blue?”)

There weren’t many precedents for what Berglund was trying to do. A hockey puck-shaped device called Lady-Comp has been around since the 1980s. It uses an attached thermometer to record temperature fluctuations and determine when it’s safe to have unprotected sex—not as convenient as a smartphone and, at $500, about the cost of one. A handful of period-tracking apps emerged around 2013, including a promising one called Clue created by a Danish woman named Ida Tin. A month later, PayPal co-founder Max Levchin unveiled Glow, aimed at helping women get pregnant.

As 2014 dawned, the couple began planning Natural Cycles’ official introduction. Sweden quickly emerged as the obvious initial market: Berglund was born and raised six hours south of Stockholm; English and technological literacy are high there; and it’s home to a vibrant startup scene that includes Spotify and King (maker of Candy Crush), and thus a large pool of talent. The couple moved in January 2014, with Berglund as chief technology officer and Scherwitzl as chief executive officer.

“It was not so scary in the beginning, because I didn’t feel like we had much to lose,” Berglund says. “Worst-case scenario I’d spent one year developing this app—which was something I wanted to learn how to do, anyway—and with that experience I could get a job.” The biggest sacrifice came following the arrival of their firstborn, a daughter named Alba, in mid-2014. Natural Cycles was just getting off the ground, with one or two people employed in marketing and no other developers apart from Berglund, making it feel impossible for her to step away. The Swedish government grants parents 16 months of paid leave to be split between them, and rather than use that money to take time away from work, they hired a nanny so Berglund could return to the company part-time beginning three weeks postpartum. “I’ve never heard of any other Swedish mom who’s done that,” Berglund told me. “It was a rough time.”

Berglund and Scherwitzl began working with researchers to build a body of clinical evidence about Natural Cycles’ effectiveness, with an eye toward getting an official designation as a contraceptive. In Europe they first sought to be categorized as a class IIb medical device, which is considered medium risk and subject to special controls. They thought, “If we manage to get this higher risk class, no one can complain—it’ll be our protection against skepticism,” Berglund says. But when the company approached the various European agencies that approve and certify medical devices, no precedent existed for a mobile app to be considered class IIb, and the bodies gave conflicting answers about which class the app should belong to, if any at all.

Scherwitzl says this left them in a legal gray zone, unclear about what claims they could make. Confident that they could scientifically justify doing so, they began marketing Natural Cycles as a contraceptive—until November 2015, when the Swedish Medical Products Agency served the company with an injunction. Natural Cycles couldn’t market itself as anything more than a fertility monitor, the MPA said, until it gained clearance as a class IIb device. “The MPA, despite all the troubles they caused us short term, helped us forge a path in the European regulatory maze by simply making a decision of what risk category we belong to,” Scherwitzl says. In February 2017 a German regulatory body called Tüv Süd categorized Natural Cycles as IIb, clearing the way to market the app as the first digital contraceptive.

In the nine months following European clearance, subscription revenue jumped from about $100,000 per month to about $1 million per month. That September, Natural Cycles announced that it had secured $30 million in venture capital funding, by far its biggest round to date, which would allow Berglund and Scherwitzl to expand their team.

Berglund and Scherwitzl began 2018 on a high. “Things just looked great, so our state of mind was good,” Berglund says. Then, on Jan. 11, the Swedish news agency Siren reported that of the 668 women who’d sought abortions in the past four months at Södersjukhuset, one of Stockholm’s largest hospitals, 37 had been relying on Natural Cycles for birth control. The hospital had reported the app to the MPA, which said it would start an investigation into the company and its medical claims.

Berglund was caught off guard but says she didn’t initially worry; the numbers appeared to be well within the margin of effectiveness in their published research. Other Swedish outlets picked up the story, including the public broadcaster SVT and the tabloid Aftonbladet. The company posted a statement on its website: “No contraception is 100 percent effective, and unplanned pregnancies are an unfortunate risk with any contraception. … As our user base increases, so will also the amount of unplanned pregnancies coming from Natural Cycles users. This is an arithmetic truth applicable to all contraceptive methods.” It promised to work with the MPA and to start an internal investigation into each reported failure.

“Then rather quickly I had a number of tough TV interviews, and more media contacted us, and I realized this is not good for our reputation,” Berglund says. The story caught fire worldwide. “Contraceptive app blamed for accidental pregnancies,” read the New York Post’s headline. CNN and Business Insider called the app “under fire,” and the Guardian said, “The startup is now on the defensive.” Within the first week, the number of average daily sign-ups, especially in Sweden, fell precipitously. In July the Guardian published a widely shared personal account by Olivia Sudjic, a British novelist who’d sought an abortion after using the app. “I was sold on shiny promises, a sleek user interface, and the fact that a former CERN physicist, Elina Berglund, was at the company’s helm,” Sudjic wrote. “But four months in, it failed. Berglund helped discover the Higgs boson; but it turns out her algorithm couldn’t map my menstrual cycle.”

In September the MPA finished its investigation, vindicating Natural Cycles’ effectiveness claims. “Our conclusion is that the number of unwanted pregnancies during the assessed time period is consistent with data shown in the clinical evaluation included in the certification documentation,” Mats Artursson, an investigator at the agency, said in a statement. But by then, the damage to Natural Cycles’ reputation was done. Virtually every story written about the company since mentions the Södersjukhuset abortions, often referring to Natural Cycles as “controversial.”

Natural Cycles isn’t one-size-fits-all: Users for whom getting pregnant would be a catastrophe are better served by something such as an IUD, because the best contraceptive is one you can forget about. The app is far from effortless to use correctly: It’s crucial to remember to take your temperature at roughly the same time most mornings and before doing anything else. Irregular sleep patterns, illness, travel, and substance use can yield more red days that require abstinence or condom use. The early marketing of the app often failed to make these things clear. The company relied heavily on social media influencers but didn’t give guidance on what they should and shouldn’t say. Ella Grace Denton, a prolific poster of selfies from London, for example, began using the app in mid-2017, when she was 22, and talked up on Instagram how it was “natural” and how empowered using it made her feel, but didn’t mention its 7-in-100 expected failure rate with typical use or that it shouldn’t be used by women younger than 18 years old.

It’s Tough Being the First Birth Control App

I visited Natural Cycles in Stockholm in December, almost a year after the controversy had begun. Its open and airy headquarters encompass the fifth floor of a red brick building with walls and furniture in gray and salmon. Conference rooms all have the startup-standard quirky names—in this case, they’re named after female trailblazers such as Malala Yousafzai, Margaret Sanger, Beyoncé, and Berglund herself. A bowl of condoms with the slogan “Red day? Use me” on the wrapper decorates the front desk, and the unisex bathrooms offer an assortment of tampons and maxi pads. Between this office and Natural Cycles’ satellites in Geneva, Berlin, New York, and the U.K., the company employs almost 100 people, representing 27 nationalities. The majority are women, even in the research and development department.

In Stockholm and in other conversations since then, I was struck by how candidly the co-founders and their colleagues acknowledged the missteps they’d made prior to the Södersjukhuset incident and by how they’d reconsidered their approach afterward. Gone, for example, were television and podcast commercials that reached too broad an audience. “It’s not for someone who is 20 years old and single and partying,” says Lars Jörnow, a partner at EQT Ventures, which invested €15 million in Natural Cycles. The company dramatically pared back the number of social media influencers it pays and now limits them to women older than 25 and in stable relationships—mirroring the profile of Natural Cycles’ indicated user. The company has expanded its medical affairs team to include epidemiologists and fertility doctors in Sweden, Germany, and the U.K. It also created a proper communications team to quickly answer questions and correct misunderstandings. For Scherwitzl, the controversy underscores how much Natural Cycles, by removing the patient-doctor checkpoint, has changed the way women access birth control. “That direct-to-woman/patient communication comes with a greater responsibility than ‘regular’ pharmaceutical advertising that drives people to doctors,” he says.

Natural Cycles has also sought better relations with Sweden’s midwives. The country is one of the world’s most secular: Public schools teach comprehensive sex education, government subsidies make the pill cheaper than condoms, and abortion is almost stigma-free, legal through 18 weeks, and can be easily obtained for no cost at public hospitals. Midwives care for most abortion patients, and it was midwives who first raised the alarm about Natural Cycles to the MPA. Seeing users for whom the app hadn’t worked, they may have thought the failure rate was higher than what the full data set showed, says Anita Kraker von Schwarzenfeld, who joined Natural Cycles as its vice president for science and communications in mid-2017 from Bayer. “We definitely should have reached out earlier,” von Schwarzenfeld says. The company has since arranged one-on-one meetings with health-care providers and presented research at medical conferences throughout Europe and North and South America.

Natural Cycles still has its critics, of course. The research done so far on the app’s efficacy has been funded by the company, which isn’t uncommon in the health-care industry but still makes some people uncomfortable, and it hasn’t included a randomized control trial. Before leaving Stockholm, I met with Lena Marions, a gynecologist at the women’s clinic at Södersjukhuset. Fewer Natural Cycles users are reporting to the hospital now for abortions, and the upside of last January’s controversy was that it sparked discussion about how various contraceptives work, she said. “If you don’t use any method at all, it’s much better,” she granted of the app. But she disagrees with its labeling. “It’s not a device. It’s software. Condoms on red days—that’s the contraceptive,” she said. The hospital regularly reports to the MPA when a medical device has failed, as it did with Natural Cycles. For women who tell her and her colleagues that they would absolutely have an abortion if they got pregnant, “we say, ‘Then you shouldn’t use Natural Cycles and not even the pill or condoms. You should use an IUD.’ ”

Although the largest concentration of Natural Cycles users lives in the U.K., Berglund and Scherwitzl now see the U.S. as their most important market. In the week after they got FDA clearance in August, they say they saw their biggest jump yet in Americans downloading the app and signing up for subscriptions. A month later, after more than four years in Sweden, they moved with their 4-year-old daughter to the family-friendly Park Slope neighborhood of Brooklyn, N.Y. When I met with Berglund in January at the company’s shared workspace in Manhattan’s Financial District, overlooking selfie-taking tourists in front of the Wall Street bull statue, she told me it was important that the founders personally establish the company’s U.S. presence, so they could hire the right core employees and replicate the open culture they’d created in Stockholm.

The U.S. expansion comes at a time of heightened skepticism regarding technology companies and their drive to amass data on virtually every aspect of our lives. Some women’s health apps have failed to protect their users’ privacy: Consumer Reports discovered in 2016, for example, that security flaws in Glow “might have let someone with no hacking skills at all” access user data such as abortion history and preferred sex positions. Just this February, the Wall Street Journal reported that Flo, a period tracker founded in 2015 that now claims 28 million users, reported to Facebook when a user was menstruating or had begun trying to get pregnant. Natural Cycles has—so far—avoided such revelations. In part, Scherwitzl says, that’s because the app isn’t free, as almost all of the others are, and the company doesn’t sell or share data. As part of its regulatory clearances, Natural Cycles is required to mitigate safety risks for users, including risks to their data and online security. No matter where the product is used, the company abides by Europe’s General Data Protection Regulation, which requires companies to obtain consumers’ consent before collecting their data and to delete data that’s no longer needed.

Natural Cycles has been expanding its suite of services, including longer-term fertility predictions, so users can plan a honeymoon or vacation, and it recently concluded a pilot program in Sweden to help women trying to get pregnant determine when to seek help from a fertility clinic. A new mode available on the app, which helps users monitor a pregnancy, could be enhanced to detect signs of a miscarriage, Berglund says. And after years of focusing on software, she says, she hopes to improve the hardware by offering a Bluetooth-connected thermometer that communicates automatically with the app.

Maintaining government clearances will continue to slow down the business: Natural Cycles has to append new clinical data to regulatory documents, for example, before it can make significant updates to its core algorithm. But among the upsides, one in particular could dramatically expand the app’s user base in the U.S.: The Affordable Care Act requires insurers to cover contraception. Natural Cycles isn’t yet listed among the accepted methods at, but Berglund and Scherwitzl say that, as an FDA-cleared contraceptive, it should be. Figuring out how to get there will be a main objective this year.

For now, they’re focused on welcoming their second child, a boy they’ll name Elio. Using her last menstrual period, as is common, Berglund’s doctor calculated her due date as April 20. But Berglund thinks she knows better. Her algorithm pegs it at April 19. —With Niklas Magnusson

To contact the editor responsible for this story: Jillian Goodman at

©2019 Bloomberg L.P.