Natural Cycles works by determining a woman’s fertility cycle through temperature measurements input by the user, as well as menstruation dates. If it is safe to have unprotected sex, the app displays a green light.
A clinical study in 2015 found the app to be as effective as the pill in preventing pregnancy from unprotected sex. However, sexual health experts warn that fertility apps can be complicated and require instructions to be strictly followed if pregnancy is to be avoided.
“Women who wish to use fertility awareness-based contraception are advised to receive guidance from a qualified teacher to learn how to effectively monitor the different indicators,” Diana Mansour, vice president for clinical quality at the Faculty for Sexual and Reproductive Healthcare, said in a statement.