Contraception App Approved by FDA The approval of the app Natural Cycles marks the first time the U.S. Food and Drug Administration (FDA) has approved a birth control app marketed as a mode of contraception. Dr. Terri Cornelison, U.S. FDA, via ABC News Using a woman's daily body temperature data and menstrual cycle information, the app calculates the fertility of the user. Dr. Terri Cornelison, U.S. FDA, via ABC News According to the FDA, in clinical studies involving more than 15,000 women, the app had a "perfect use" failure rate of 1.8 percent. Taking into account when users either ignored the apps recommendation or used it incorrectly, the studies found a "typical use" failure rate of 6.5 percent. According to ABC News' chief medical correspondent Dr. Jennifer Ashton, The use of Natural Cycles in Europe has been met with controversy by women who reported unwanted pregnancies.