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Tracking Your Menstrual Cycle

A shortening in cycle length is often the first sign that perimenopause has begun. Tracking is the key to seeing this.

Why should I track?

Tracking your menstrual cycle can help you see the increased cycle length variability as you approach menopause, which can give you verification that hormonal changes are beginning and may be what’s behind your new “experiences” (aka symptoms) like disrupted sleep, changes to mood, new brain fog.
When my Ob/Gyn asked me if my periods were regular, I said YES, because I was getting a period each month. It wasn’t until I tracked my cycles that I realized they were shortening. What a relief — what I was experiencing now made sense in light of that!

Nina

 

3 things to keep in mind when tracking your cycle

  • Initially, you might see your menstrual cycle lengths shortening (i.e. periods coming closer together). This can tell you that perimenopause has begun. Seeing this was comforting to me as allowed it me to know I could attribute my new mood and sleep changes to shifting hormonal patterns.

    Note: You see this shortening over many cycles. See the left graph below. These are the average of all cycle lengths in a calendar year.

  • Later you might notice that your menstrual cycles start to lengthen (i.e. periods coming further apart). A sign that the final menstrual period is getting closer. See the right graph below.

  • You might also see increased variability in your cycle lengths (i.e., 44 days, 28 days, 34 days).

CYCLE DATA

First — cycles getting shorter

Tracking your menstrual cycle is helpful to see subtle changes that indicated hormonal shifts are occurring. This image shows a shortening of cycles.

Updated February 2026

Then — cycles getting longer

Tracking your menstrual cycle is helpful to see subtle changes that indicated hormonal shifts are occurring. This image shows a lengthening of cycles.

The chart below shows the difference in days between consecutive cycles approaching menopause.

So if one cycle is 30 and the next is 35, the difference in days would be 5. You can see how much variability increases as you approach the final menstrual period.

A graph showing how the days between consecutive cycles gets much longer as you approach the final menstrual period

 

Each person’s experience is unique. Read about what we learned from tracking our own perimenopause symptoms.

Read more

How should I track my menstrual cycle?

The simplest tracking

The simplest way to track your menstrual cycle is note the day your period starts in your calendar, a note on your phone or in an app. This will allow you to calculate cycle length (see below). Cycle length is one of the first things to change on the path to menopause.

Note: If you are on the pill, have a progestin IUD, or have had an ablation, tracking your menstrual cycles won’t apply — but recording symptoms will still help you learn a lot about what is going on for you.
Tracking Your Menstrual Cycle
temperature rising signals ovulation has occurred

More involved tracking can tell you if you’ve ovulated and when your period might start

Your overnight body temperature called Basal body temperature (BBT) is your body’s temperature fully at rest, the lowest temperature of each day. It can give you clues about whether you are in the follicular phase or the luteal phase, whether you have ovulated and when your period may start.

A wearable device that tracks your nightly temperature can tell you when you’ve ovulated. Nina has used an Oura Ring for many years and when her cycles were coming monthly, she could see her temperature rise after ovulation. It would rise for 11-14 days (luteal phase). The first morning when she saw that her temperature had dropped overnight, her period would begin within 24 hours.

What information should I include when tracking my cycle?

Cycle length: The number of days between Day 1 of one cycle and Day 1 of the next.

Symptoms & timing: Take note of the symptoms you’re experiencing and when in your cycle they occur.

Tracking periods, for some, is associated with trying to conceive.

So this is a good place to remind you that you can still get pregnant during perimenopause.