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There Is Now an App to Foolproof 'The Rhythm Method' of Birth Control

Having to remember to take pills every day is a bummer. So is using condoms if you're in a long-term, monogamous relationship. Two Swedish scientists have created an app to help you with these problems.
February 6, 2015, 5:37pm

Say bye-bye to those pesky birth control pills. Photo via Flickr user Delightfully Tacky

Swedish scientists have created an app that allows people to prevent pregnancy without suffering maniacal condom paranoia, being pumped full of hormones, or worrying about the potential complications of intrauterine devices (IUDs).

The app is called NaturalCycles, and it uses the fertility awareness method many menstruating people have used since time immemorial. Compared to the multitudes of people who have used this method, though, this app claims to be 99.95 percent effective in preventing pregnancy. I highly doubt most people who track their own cycles can claim the same.


To use it, menstruating people must simply take their temperature upon waking up and record the temperature in the app. The app funnels all the data provided into an algorithm, and tells you whether it's a "red day" or a "green day." On green days, you're safe to have unprotected sex without worrying about pregnancy. On red days, condoms are recommended.

Aside from the temperature recordings, users must also record when they have their periods. And if they're super Type A, they can also use ovulation strips and record the data from that, too. The more data, the more accurate the app's algorithm will be, and thus the more condom-free, stress-free fucking the user gets to engage in.

But if you fuck it up—that's to say, you forget to supply the app with the data it needs—it will still have you covered. You'll simply have more "red" days on your calendar, and if you're smart, you'll use a condom on those days. If you're not smart, you might wind up procreating.

Doctors Raoul Scherwitzl and Elina Berglund, partners, are both former physicists, and they created the app because Berglund was sick of being on the pill. She'd been on it for a decade, and wanted a hormone-free alternative.

In case you're wondering about her credentials: Berglund was formerly a researcher at CERN, and she was one of the physicists who discovered the Higgs Boson, which won the Nobel Prize in 2013. So yeah, feel free to trust her. Also consider that Swedes are great at acknowledging and celebrating the vagina and its many magical functions.


"Basically, we provide a hormone-free birth control method," Scherwitzl said. "You get to know your body, rather than doing something to it."

So far, the app has about 17,000 active users. But it must be acknowledged that this is really a tool for the monogamous. Obviously, it prevents only pregnancy. It doesn't offer any protection against the contraction of sexually transmitted infections (STIs). This app, then, is probably best-suited to somewhat long-term partners who only have sex with each other and who have been tested for STIs. If you want to bonk someone outside of your main partnership, you might want to employ the dreaded condom, even on a green day.

NaturalCycles' 99 percent efficacy has been clinically tested by tracking the cycles of 317 women. I asked Scherwitzl if he thinks that's a big enough sample size, and he says it is for now. He says they'll do more in the future, because that's how they'll get doctors to recommend their method.

On top of the clinical trial, he and Berglund tested it out themselves before launching the company, and successfully avoided pregnancy the entire time. Then, they decided to have a child, so they flipped the way they used it and became pregnant within months.

I ask if there are any warnings they would give on human error. Natural family-planning methods come with their share of risks. About 24 in 100 women who use fertility awareness as their main method of contraception will become pregnant within the year. But because the app knows when its user ovulates, which people often don't on their own, that number can easily be much lower with the app's use.


When asked if the app takes into account the fact that sperm can live in the body for up to five days following intercourse, Scherwitzl replied swiftly. "Yes," he said sassily. "Of course we account for that risk. Otherwise we would not be 99 percent safe." And from their website:

"The fertile window ends with the ovulation day and begins 5 days before, since sperm can survive 2-5 days in the female body. Only during these 'red' days can the woman get pregnant through unprotected sexual intercourse."

The day will simply become a red day if one forgets to record, and then the onus is on them to use a condom.

"It's like any birth control," he says. "You have the perfect use, and then you have the typical use." He uses the pill as an example. Many people forget a pill, or take medication that alters its efficacy without realizing it. And even with perfect use of condoms, about two percent of menstruating people will become pregnant. With typical use, it goes up to about 20 percent.

Planned Parenthood says natural methods straight up are not for you if you "can't keep careful records." So, for instance, if you're high all the time (or have certain medical conditions), you may be at risk.

"The nice thing with us is if you forget to record, that's okay," the app's co-creator says. "The algorithm will become more and more skeptical and will say, 'Like okay, this day, even though it could have been a green day, you [didn't pay attention].'"


It costs less than the pill does for people without drug coverage: $68.90 per year. Included in the cost is a thermometer, and payments can be made monthly or quarterly.

Scherwitzl calls the app "a nice solution for all." Users can have more spontaneous sex, and people who find condoms uncomfortable don't have to stress about them.

He argues the push from the medical community to go on the pill or, in far fewer cases, to have an IUD inserted, can "blind" people. Patients are told these methods are the only way, and doctors seldom mention that, with a little care and attention, more contraception practices can be quite effective. If we really want to solve the dilemma many people find themselves in with birth control, education is the key, he says. Those who use the app correctly will no longer need to juggle the fear of pill-induced anxiety, depression, or lowered sex drive with fear of IUD complications like dislodging, ectopic pregnancy, or uterine perforation.

"[We should] talk openly about it. We don't want it to be a subject people are embarrassed about."

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