Guide
How to track your menstrual cycle — and what to look for
Cycle tracking is most useful when you know what signals to record and what patterns actually indicate something worth discussing with a doctor.
What to record — and what matters
The most useful data points are cycle length (from the first day of one period to the first day of the next), period duration, and flow heaviness. Symptoms — cramping, spotting, mood changes, pain — add context. Most tracking apps record all of these automatically once you log start and end dates consistently. The pattern over 3–6 cycles is more meaningful than any single cycle.
What counts as irregular
A cycle outside the 21–35 day range is the standard clinical definition of irregular. However, a cycle that is consistently short or long — but stable — can be entirely normal for an individual. The more reliable signal is variation: if the gap between your shortest and longest cycles regularly exceeds 7 days, that is a more meaningful indicator of irregularity than cycle length alone.
Symptoms that are always worth mentioning to a GP
Regardless of whether your cycle length looks regular, these symptoms are worth raising with a doctor: bleeding between periods, pain severe enough to disrupt daily activities, very heavy bleeding (soaking protection every hour for several consecutive hours), and periods that stop for 3 or more months without a clear cause. None of these are necessarily serious — but they are clinically significant and should not be managed with tracking alone.