Smartphone apps do a lot of things these days. They can turn on your home thermostat, test your blood-alcohol content, and even diagnose car trouble. One thing they apparently can’t do, however, is eliminate human error from processes that require consistent decision making. Such as birth control.
You may have heard of Natural Cycles, the fertility app designed by Swedish physicists. It was the first app in the world to be certified by the European Union as a form of contraception, and as of late 2017 had more than 600,000 users in 160 countries. Based on an algorithm using a woman’s basal body temperature to predict fertility, Natural Cycles was reported to have an effectiveness rate around 93 percent — comparable to that of the oral contraceptive pill.