The Natural Cycles app is a mobile application classified in the EU and by the FDA as a medical device for contraception. Technically it is a fertility awareness method
. The app contains an algorithm that analyses your temperature (measured using a thermometer) and menstrual cycle data to calculate when you are fertile, and tells you to avoid sex or use other protection like condoms on your fertile days. Unlike other fertility awareness methods it tries to minimise human error as the algorithm does the calculations and interpretations for you.