How cycles change
The NHS describes perimenopause periods this way: "They may happen more often or less often, and bleeding may get heavier or lighter. Eventually, you stop having periods altogether."
There is no fixed order to this and no fixed timeline. That variability is exactly why a cycle-prediction app, built on the assumption of a stable pattern, tends to stop being useful right around when tracking would help most.
What tends to change, without a fixed sequence
- Cycle length. Cycles can get shorter, get longer, or vary more from month to month than they used to. No single direction is "typical."
- Flow. Periods can become lighter or heavier than your baseline, sometimes both at different points in the transition.
- Predictability itself. Even before length or flow visibly changes, the gap between periods can simply stop being reliable enough to predict.
- Eventually, periods stop. Menopause is defined as 12 months without one — a point identified only in retrospect.
What to record instead of what a prediction app expects
- Start date of each period, and end date if it's easy to note.
- Flow, in your own consistent terms — spotting, light, medium, heavy.
- Anything between periods — spotting, or bleeding that doesn't fit the pattern.
- Gaps. A skipped month, or several, is itself information worth a dated entry, not just an absence of one.
This is a plainer record than a prediction app keeps, on purpose. Once prediction stops being reliable, the value shifts entirely to having an accurate log to bring to an appointment. Tracking periods and bleeding in perimenopause covers this in more depth.
What should be checked, not just logged
NHS guidance is clear that bleeding after sex, bleeding between periods, or unusually heavy bleeding should be checked by a clinician rather than only recorded and watched. Ordinary cycle irregularity is expected in perimenopause; these specific patterns are the exception worth raising promptly.
This is general information, not medical advice. HormoneLog is a tracking tool, not a diagnostic or treatment device, and nothing here can tell you whether your symptoms are normal, what they mean, or what you should do about them. Those are conversations for a clinician who knows your history.
Tracking periods and bleeding in perimenopause. · What "12 months" means. · Perimenopause vs. menopause.
More in this section
About HormoneLog
HormoneLog is an iOS app from Baker Ventures LLC for tracking perimenopause and menopause symptoms and keeping an HRT record: what you took, at what dose, from when, and what changed afterwards. It is built for the appointment, where "it has been bad lately" is worth far less than a dated record of frequency and severity. The app is in development.
HormoneLog is a record-keeping tool. It does not diagnose, does not score you, and makes no claim about symptom relief. The guides on this site link to NICE, the NHS, the Menopause Society and peer-reviewed sources, and say plainly where the evidence is thin. Everything here is free and needs no account.
Questions and answers
How do periods typically change in perimenopause?
The NHS describes periods becoming irregular, and either lighter or heavier, before stopping altogether. The changes don't follow a fixed order or timeline, and they vary considerably between people.
Is it normal for cycles to get shorter before they get longer?
Cycle length changes are common and vary by person — some notice shorter cycles first, some longer, some more variation month to month rather than a clean trend in one direction. This is exactly why a record of your own pattern is more useful than a general rule.
When does irregular bleeding need to be checked rather than tracked?
NHS guidance is that any bleeding after sex, between periods, or heavier than usual should be checked. This page is about tracking ordinary cycle change, not a substitute for that guidance.
Do cycle-tracking apps still work during perimenopause?
Apps built around predicting a regular cycle tend to become less useful as the cycle itself becomes less predictable. What still works is a plain dated record of start dates, flow, and anything unusual — prediction isn't the point anymore, the record is.
HormoneLog. “How cycles change.” Baker Ventures LLC, September 8, 2026. https://hormonelog.bakerventuresstudio.com/guides/how-periods-change-in-perimenopause/