Use the Cycle Tracking app to log details about your menstrual cycle. You can add flow information and record symptoms such as headaches or cramps. Using information you’ve logged, the Cycle Tracking app can alert you when it predicts that your next period or fertile window is about to start. In addition to using data you’ve logged, Cycle Tracking can also use heart rate data to improve predictions. If you wear Apple Watch to sleep each night, the app can use wrist temperature (on supported models only). For more information, see the iPhone User Guide.
Important: The Cycle Tracking app should not be used as a form of birth control. Data from the Cycle Tracking app should not be used to diagnose a health condition.