Natural Cycles is a birth control app. It is hormone-free and is intended to be a natural, non-invasive contraceptive method. The app is produced by Natural Cycles AB, a company co-founded by Elina Berglund, a former CERN physicist. Natural Cycles is available as a method of birth control in the US, Europe, Canada, Australia, Singapore, and Brazil. Outside of these countries, it is intended for fertility monitoring.
Natural Cycles works by tracking a user's menstrual cycle and basal body temperature (BBT), with the option to include urinary luteinizing hormone (LH) to identify fertile days. The app then uses an algorithm to predict fertility, informing users of fertile (red) and non-fertile (green) days. Users must either abstain from sex or use protection on fertile days to prevent pregnancy. The app can be used with a basal thermometer, Oura Ring, Apple Watch, or the NC° Band to track temperature. The cost of Natural Cycles varies depending on the subscription plan. A monthly subscription costs approximately $16.99 per month, while an annual subscription costs $119.99. The annual subscription includes a free basal thermometer. The Oura Ring costs separately between £349 to £500. Natural Cycles is available for download on iOS and Android devices.