Why should I track?
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
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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.
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You might also see increased variability in your cycle lengths (i.e., 44 days, 28 days, 34 days).
First — cycles getting shorter
Then — cycles getting longer
Updated February 2026
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.
How can 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. Cycle length = The number of days between Day 1 of one cycle and Day 1 of the next. Many apps will do this for you. If you do use an app, be sure read the privacy policy.
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 other information should I track?
Symptoms: Which symptoms are showing up? Do some occur together? Are these things you’ve experienced before but they are more intense? Or are these totally new for you?
Timing:When in your cycle they occur? Mid-cycle at ovulation? Right before your period? During your period? When do you feel best?
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.