Stockholm-based Natural Cycles has received the FDA’s 510(k) clearance to update the labeling and extend the varieties of third-party thermometers and wearable devices that can be used with its Natural Cycles birth control app.

The app is based on an algorithm that analyzes a woman’s daily fertility status based on basal body temperature, heart rate and other biometric data. Until now, users have had to use a basal thermometer to take their daily temperature and enter it manually.

Natural Cycles is currently developing its own device to go with the app, which was previously cleared for use in Europe.