The app, which is the brainchild of a Higgs Boson physicist, has been certified as a valid birth control in the European Union.

Image via Natural Cycles.

When the Large Hadron Collider finished its first run in 2012, Elina Berglund was thrilled. Who wouldn’t be? But after a while, she felt a bit lost, like she wanted to try something different.

“It’s impossible to top that,” she said. “So I thought, why not try something completely different?”

She looked to her own personal life for inspiration. She’d been relying on a hormonal birth control implant for ten years, but she wanted to give it up. So while she was still working at CERN, European Organization for Nuclear Research, she researched alternatives, finding several apps on the market — but none were good enough. So she decided to make her own.

She and her husband launched the app called Natural Cycles, in Sweden in 2014. Billund says it wasn’t that big of a leap since her previous work.

“Instead of looking for the Higgs particle, you’re looking at women’s temperatures and fertility data, which is a lot of fun,” she says.

Her approach was scientific, and results were published in 2016, in The European Journal of Contraception & Reproductive Health Care, receiving over 17,000 views, which is quite a lot for a journal study.

What makes this app different

Natural Cycles relies on measurements taken with a highly accurate thermometer and analyzes personal details about menstruation. As the woman’s temperature changes with the menstrual cycle, the app turns green when the risk of pregnancy is low, and red when the risk is high.

The idea itself is not new — as Dr. Paula Castaño, an OB-GYN at Columbia University says, women have been charting their period since forever. There are a thousand apps you can find already, but this takes an extra step, having a more scientific approach, using statistical analysis of the temperature, instead of just the calendar.

“We’ve just had to use initially paper calendars, and then calendars on our phones, and ultimately now specific apps that can help us do that, Castaño” told NPR.

Efficiency

Billund presenting her project at Le Web.

When it comes to contraception, the calendar is about as bad an approach as you can get. Used perfectly, the pill has an effectiveness rate of 99.7 percent. In the real world, where not everyone takes their pills perfectly, that efficiency drops to 92 percent. In the clinical study mentioned above, which included 4,000 women, Natural Cycles scored an accuracy of 93 percent. It’s definitely not perfect, but it’s quite remarkable.

“You could argue that the app may be comparable to someone who may not be taking the pill very consistently or accurately,” says Dr. Ellen Wilson, an OB-GYN at the University of Texas Southwestern. “But if you take the pill on a regular basis and don’t miss any, I don’t think you’re going to have a natural family planning method that is going to compare.”

Billund says she doesn’t want to replace existing methods, she just wants to add a new spin to an ancient method, making it more accurate and more reliable. Dr. Castaño also points out that some women simply want something natural. You don’t have to take any pills, you don’t have to ingest or inject anything — you just take your temperature.

“So it’s great for them to have something that they can use that’s based on some sound medical evidence,” she says. “Very few apps even have that.”

Indeed, this is the first app officially approved in Europe.

Natural Cycles already has more than 300,000 users and is making quite a profit, at a price of $10 / month (much cheaper if you buy yearly). There are no ads, and the data isn’t shared with any third party. So far, most users are from Northern Europe, but Billund wants to expand to other markets: especially the US.