Periods in perimenopause: what to track when the pattern stops being a pattern
Cycle apps are built to predict, and prediction is the first thing that stops working.
When cycle length swings from three weeks to three months, a predictive app does two unhelpful things: it produces confident wrong dates, and it smooths the variability into an average. The variability is the clinically interesting part, and the average is the one number that hides it.
Record facts instead of forecasts: start date, end date, how heavy by a countable measure, any bleeding between periods, pain, and anything unusual.
Make "heavy" countable, because it is a word two people use for entirely different things. Products used per day. Whether you changed during the night. Whether you changed more often than every two hours. Flooding. Clots, and roughly what size.
Some bleeding should not wait for a routine appointment. Health services publish specific guidance, including on bleeding after a year without periods, bleeding after sex, and unusually heavy bleeding. Read your own health service's guidance and act on it, rather than on a general article, and seek advice rather than waiting to see whether it settles.
HormoneLog does not predict. It records, because a confident date it cannot support is worse than no date.
What to record
| Field | Example |
|---|---|
| Start date | 3 September |
| End date | 9 September |
| Heaviest day, countable | Day 2: changed every 90 minutes, twice overnight |
| Clots | Yes, day 2, up to about the size of a 10p coin |
| Between-period bleeding | Spotting on 21 and 22 August |
| Pain | Day 1 to 2, needed painkillers, missed a morning of work |
| Anything else | Started a new medication on 15 August |
Six months of that is a genuinely useful clinical document. It shows cycle length and its range, how heaviness is changing, whether there is intermenstrual bleeding, and how much it is affecting your life, which is the thing that most often decides what happens next.
Why the variability is the point
A perimenopausal cycle history frequently looks like: 24 days, 31, 28, 52, 22, 40. An app that reports "average 33 days" has described none of that.
The range and the pattern of change are what a clinician is asking about when they ask what your periods have been doing, and it is a question almost nobody can answer accurately from memory once the pattern has broken. Perimenopause versus menopause.
Heaviness, in language that travels
"Heavy" is not a measure. These are:
- Products per day, and how often changed.
- Changing during the night, and how often.
- Changing more often than every two hours for several hours.
- Flooding, meaning through clothes or bedding.
- Clots, and their approximate size against something familiar.
- What you could not do because of it. Missed work, cancelled plans, would not leave the house.
That last one carries more weight in an appointment than people expect, because impact on daily life is often what determines whether something is treated as significant.
And keep it in mind for the other half of the picture: heavy or erratic bleeding is a common route to low iron, and low iron produces fatigue and cognitive symptoms that are easy to attribute to something else. That is one of the specific things a record makes testable. Brain fog: what to record.
What should not wait
This page is not the authority on that, and no general article should be. Your own health service publishes guidance naming the bleeding patterns that need prompt assessment, including bleeding after a year without periods, bleeding after sex, and bleeding that is unusually heavy.
Read that guidance, and act on it. If something is frightening you, that is reason enough to seek advice rather than to wait and see. What to do when you cannot get an appointment.
What this record is for
It is preparation. It turns "they have been all over the place" into six months of dates a clinician can read in fifteen seconds, and it removes the recall problem, which is severe here: cycle history is one of the things people are most confidently wrong about, in both directions.
HormoneLog holds the record and produces no score, no prediction and no assessment. There is no threshold in it that declares a pattern abnormal, because that is a clinical judgement made by someone who can examine you and order tests.
Why tracking perimenopause symptoms is worth it. · Tracking before your appointment. · What to take to your first appointment.
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
Why do cycle tracking apps stop working in perimenopause?
Because most are built to predict, and prediction depends on regularity. When cycle length varies from three weeks to three months, a predictive app produces confident wrong answers and often hides the variability that is itself the clinically interesting information.
What should I record instead of a prediction?
The facts. Start date, end date, how heavy and by what measure, whether there was bleeding between periods, pain, and anything unusual. Variability is the signal, and a record of actual dates shows it where an average does not.
How do I describe how heavy bleeding is?
Use something countable. Products used per day, whether you had to change during the night, whether you had to change more often than every two hours, flooding, clots and their approximate size. Countable descriptions travel; heavy is a word two people can use for very different things.
What bleeding should not wait for a routine appointment?
Health services publish specific guidance on this, including bleeding after a year without periods, bleeding after sex, and unusually heavy bleeding. Check your own health service's guidance and act on it rather than on a general article, and seek advice rather than waiting to see whether it settles.
Does tracking help at the appointment?
Substantially. A clinician asking about your cycle pattern gets a much better answer from six months of dates than from a description, and the pattern of variability is often the thing they most want to see.
Does HormoneLog predict my next period?
No. It records what happened. Prediction during perimenopause is precisely the thing that stops being reliable, and an app producing a confident date it cannot support is worse than one that does not try.
HormoneLog. “Periods in perimenopause: what to track when the pattern stops being a pattern.” Baker Ventures LLC, September 7, 2026. https://hormonelog.bakerventuresstudio.com/guides/tracking-periods-and-bleeding-in-perimenopause/