The U.S. Food and Drug Administration will allow marketing for the first phone app that can be used to prevent pregnancy.
In a Friday news release, the FDA said the app, called Natural Cycles, has an algorithm that determines the days of the month when a woman will likely get pregnant based on menstrual cycle information and daily body temperature -- a contraception method called fertility awareness. The app requires women to take their temperature daily using a basal body immediately upon waking in the morning.
The app has already been certified as a method of birth control in Europe since last year. It was created by particle physicist Elina Berglund.
"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," Dr. Terri Cornelison, assistant director for the health of women in the FDA’s Center for Devices and Radiological Health, said in a statement. "But women should know that no form of contraception works perfectly, so an unplanned pregnancy could still result from correct usage of this device."
More than 15,570 women used the app for a clinical study over the course of eight months. The "perfect use" failure rate was 1.8 percent, meaning 1.8 in 100 women who use the app for a year will get pregnant because their contraceptive method failed when they had intercourse on a fertile day, or they had intercourse when the app predicted they would not be fertile.
The "typical use" failure rate was 6.5 percent, meaning women used the app incorrectly. For example, a woman may have unprotected sex on a day the app predicted they would be fertile.
In January, a Swedish Hospital blamed the app for reports of dozens of unwanted pregnancies from users, but officials with the company that marketed it noted that "unwanted pregnancies is an unfortunate risk with any contraception."