The Clearblue Fertility Monitor saves your last six menstrual cycles, and then it starts overwriting the older cycles. The monitor will retain the last set of cycle information indefinitely, even if you do not use it for a period of time. To reset the monitor, you must reprogram it, a task that is fairly easy to do.
Turn the Clearblue Fertility Monitor off.
Insert a test stick into its designated slot, ensuring it is properly placed. The monitor will not let you know whether it is in place or not while it is turned off.
Hold down the “M” button while you press the “On/Off” button. The monitor should then display the test stick symbol on the monitor.
Hold the “M” button for approximately 15 more seconds. The monitor will display the test stick symbol a second time.
Release the “M” button and remove the test stick. As long as the display screen displays “—M," the Clearblue Fertility Monitor has been properly reset or reprogrammed.