09/03/2026
Most women rule out perimenopause because their period is still regular. I understand why, and a regular period is not the proof people think it is.
One of the earliest things to change is not your cycle length. It is whether you are ovulating at all. You can have a month that looks completely normal on a calendar and not ovulate that month.
No ovulation means much less progesterone in the back half of that cycle. So progesterone can start falling while estrogen is still swinging around unpredictably, and none of it shows up as a missed period.
What it does show up as is sleep breaking at two in the morning, a temper you do not recognize, and cycles that are just slightly different in a way you cannot quite name.
If you have ruled this out purely on your age and your calendar, that is worth revisiting.