You may trust your smartphone to take you to work, to wake you up in the morning, and maybe even to unlock your home or control your security system.
Would you trust it to keep you from getting pregnant?
The Food and Drug Administration announced Friday that it had approved marketing materials for the app Natural Cycles, which is now the first-ever smartphone application approved for contraception, according to the agency.
Here’s how it works: The app uses a combination of body temperature (taken with an included thermometer), a diary for daily tracking of the ovulation cycle, and an algorithm to determine “green” and “red” days where it is safe to have sex without another type of contraception. It takes between 1 and 3 cycles for the app to be consistently confident in its recommendations, according to the app’s website.
According to the FDA, the app has a “typical use” failure rate of 6.5 percent and a perfect use failure rate of about 1.8 percent. Perfect use would mean using the app exactly as intended, tracking every day and only having sex on “green days.” Typical use accounts for some days when the directions may not have been followed perfectly.
Those numbers are relatively good. The typical use failure rate is right on par with the oral pill, which is around 9 percent, according to the Centers for Disease Control.
The app boasts better numbers than several other contraceptive methods as well. Condoms have an 18 percent typical use failure rate, and diaphragms have a 12 percent failure rate, according to the agency. The most reliable methods include the hormonal implant (0.05 percent) and the intrauterine device (0.2 - 0.8 percent.)
Using a traditional fertility-awareness method with a calendar can cause a range of results, but the CDC estimated the overall failure rate for those methods was 24 percent.
“Consumers are increasingly using digital health technologies to inform their everyday health decisions, and this new app can provide an effective method of contraception if it’s used carefully and correctly,” Terri Cornelison, assistant director for the health of women in the FDA’s Center for Devices and Radiological Health, said in a news release. “But women should know that no form of contraception works perfectly, so an unplanned pregnancy could still result from correct usage of this device.”
Indeed, the app came under controversy after 37 out of 668 women in Sweden reported unplanned pregnancies while using the device, ABC News reported.
But Natural Cycles co-founder Raoul Schewitzl told Business Insider those numbers were expected, because sometimes people don’t follow the app’s directions exactly.
“In the end, what we want to do is add a new method of contraception that women can choose from without side effects,” Scherwitzl told the site. “I think there are many women who this will be great for.”
The system is available for $10 per month of $80 per year from its website.