Birth control app Natural Cycles has come under fire for its lack of effectiveness. The Stockholm-based app is being blamed for 37 unwanted pregnancies, reported Södersjukhuset hospital after staff saw a rise in patients seeking abortions.

While the app’s tech interface could possibly be blamed for the unwanted pregnancies, there is reason to believe it’s actually the temperature method itself that is at the root of the problem. After all, there is a reason the method isn’t as popular as the pill or even condom use. It’s clinically not as effective because of the high chances of error during use.

Natural Cycles, currently being used by more than 500,000 women and seeking FDA approval, is built on the “Temperature Method” of birth control, a form of contraception that falls under the Fertility Awareness Methods category. It uses a woman’s body temperature as a signal to have safe, unprotected sex during ovulation.

The app works by syncing with a thermometer, sent to the user by Natural Cycles, to measure their body temperature daily and generate a green or red light to indicate safe or unsafe intercourse.

The Swedish news outlet SVT reports the 37 unwanted pregnancies come from a group of 668 women who sought abortion at the hospital from September 2017 through the end of the year, over just four months.

According to the FAQ page on the Natural Cycles site, the app claims that clinical studies have shown the method to be effective as a contraceptive method and is “comparable to other conventional methods.”

“During one year, five women out of 1000 get pregnant due to a falsely attributed green day,” the site says. “Seven women out of 100 get pregnant during one year due to all possible reasons (e.g. having intercourse without protection on red days or failure of the contraceptive method used on red days).”

The hospital, however, clearly hasn’t seen the effectiveness being touted.

“We have a duty to report all side effects, such as pregnancies, to the Medical Products Agency,” midwife Carina Montin told Siren.

The reported 37 unwanted pregnancies show that the app may not be the only factor to blame: The temperature-calculating method itself isn’t very practical.

According to Planned Parenthood, the method’s “safe” window to have intercourse begins after the increase in body temperature lasts for at least three days. It ends when the temperature drops just before the next period begins.

“During your safe days, you can have unprotected vaginal sex. On your unsafe (fertile) days, avoid sex or use another method of birth control,” the Planned Parenthood site explains.

The problem with Natural Cycles’ claim is that the method is only about 76 to 88 percent effective, according to Planned Parenthood. That’s significantly less than the pill’s 91 percent and IUDs’ 99 percent protective rate. Not to mention the temperature method doesn’t protect at all during sex on “off” days.

But Natural Cycles isn’t phased, releasing a statement in defense of its app.

“No contraception is 100 per cent and unwanted pregnancies is an unfortunate risk with any contraception,” the statement reads. “To have 37 unwanted pregnancies out of the 668 mentioned in this study at Södersjukhuset means that 5.5 percent of women who stated they used Natural Cycles also had an unwanted pregnancy. This is in line with what we communicate as the risk of unwanted pregnancy with typical use, and which is comparable to other types of contraception.”


When and how do most Americans lose their virginity? Check out this video to find out.