If you log a period before Cycle Day 16 (CD16), the algorithm will not start a new cycle but will continue counting your cycle days as if you’re still in the same cycle.
The algorithm will only start a new cycle with a period entry if your cycle has lasted for at least 15 days.
Cycles that are shorter than 16 days are considered irregular cycles. To learn more about irregular cycles and what could cause them, please follow this link. If you feel any reason for concern about your cycle, we encourage you to contact your healthcare professional.
How to log cycles that are shorter than 16 days
If you get your period before CD16, we recommend that you log the bleeding as Spotting. You can also use the notes section in the Add data page to describe the bleeding if you would like.
Once you reach CD16, you can log any bleeding you have on that and the following days as Period. Doing this will allow you to keep track of the bleeding, and the algorithm will then start a new cycle from the period entry on CD16.